It is an interesting to see how the market has stabilized for computer monitors, the 27" 2500x1400 category has stabilized and the new UltraHD are not quite affordable yet. So here are some choices. Going through  Anandtech and TNTCentral as technical site, then  Amazon customer ratings for reliability and having a quick over from Wirecutter was a good plan.
The summary is:

• For gamers. The new ASUS RoG Swift PG27iQ seems like a great value choice. 2550x1440 running at 144 hertz. Wow! $800 of joy when it comes out in September. • For general development and office work. ASUS PB27Q is the value choice at$490 (From Newegg) while if you can afford it the Dell U2713HM has slightly more perfect performance at $615 (Amazon) or$625 from Best Buy (they have their 2% reward program, so the price is about the same as Amazon in effect).
• For television folks. Best thing to do is to wait a little the price of UltraHD is coming down, but it isn't mature yet.

First a decoder ring:

• Resolutions. There is an incredible umber of terms for this, but the most relevant are:
• 1080p or HD. This means 1920x1080 pixels. P means that it is using progressive scanning, so every frame, all 1080 lines are refreshed.
• 1440p or WQHD. This is 2550x1440 pixels so about 40% more resolution than 1080p. Doesn't sound like it, but it definitely makes a difference. It is the sweet spot right now
• 4K or UltraHD. They change the terminology to refer to the width and not the height, so this is typically 3840x2860 and on a 27" monitor, it is mainly used to pixel double for smoothness
• 8K also UltraHD. This is an eye-popping 7680x4320. These are basically impossible to get but we can all wish 🙂
• Refresh rates.
• 24 or 30. Movies are usually shot at 24 frames per second. The old standard for traditional film. It gives a nice quality, but it is low enough that if you drag a window across, you can see the judder (or lag). Most HDMI is limited to 30 fps by bandwidth at 4K resolutions, so you have to make sure you have DisplayPort (see inputs below)
• 60 fps. This is the traditional frame rates for computer monitors (in the old days, there was also 72 hertz). It gives a nice feel
• 120 or 144 fps. For gamers, this is a wonderful frame rate. Means that a quick scan across the battlefield is very smooth. Not really needed for say writing software.
• nVidia Gsync. A technology that allows variable refresh rates at the push of a button. Great for gamers.
• Panel types. These are the different technologies to build panels. The other variable is how many bits per color it uses
• TN. This is relatively less bright and lower angle of view but is very fast. So you see this in gamer products. Older ones used 6-bits/color so you got lower gamut or range of colors
• VA (Vertical Alignment). These are general at true black and come in HVA and MVA flavors. Confused yet? They are super high contrast
• IPS (In Plane Switching). The current "best" in that it is very bright
• Backlighting. This is mainly about how uniform.
• Florescent. The older technology. Very cheap now
• LED. The more desirable as it is lower power and more uniform.
• Lag. This is what gamers care about as well. It is how much delay is there from input to the actual display on the screen. Apparently people think that can see the difference between 18m and 33ms?!
• Inputs. While there are many, there are probably three that matter in this digital world
• HDMI. This is the home theater standard. The main issue is that it is limited to 1080p normally with the 1.4a standard. There is a new 2.0 standard not quite implemented that supports UltraHD
• DVI. The computer variant, needs a different cable but can show 1440p with a Dual link cable (DVI-DL)
• DisplayPort. What Apple comes with an can show 1440p, to use it with 4K, you need the 1.2 MST (multi-stream) to get 4K at 60 hertz which you need for computer displays. This 1.2 MST is extremely flaky on current builds, so the UltraHD is not quite there on inputs.

Here is what Anandtech is saying, basically the best price/performance seems to be the p27qm

• Dell UP3214q. This is the first of the deluxe UltraHD monitors and is a monster 32" wide. It is similar to the ASUS Pb279Q
• LG LG34UM95. This is an ultra-wide 21:9 monitor. At 34 inches wide, it is great for writing software as you can have lots of pages open. The panel is IPS and decent, although not good enough for photographic work, it is a good gamer. $1,000. • Samsung s27b971dg.$1000. This is a high accuracy panel intended for people doing imaging.
• Dell U2713HM. This is a slightly better panel, but at least in their view not worth the extra $100 (It is$619 at Amazon, a bit more popular but lower rating 4/5). It is an 8-bit IPS panel. It is very accurate out of the box and quite good after calibration so good for image work.
• ASUS pb278q. This is a "standard" panel with 1440p, IPS and LED lighting with decent color accuracy (after calibration) and uniformity. $550 from Amazon and it is one of the top rated monitors (4.7/5) there. It is a PLS not a IPS panel for what that is worth. • Monoprice IPS-Glass panel pro. They don't just make cheap cables at Monoprice anymore, now they have a decent low cost IPS monitor at$475. It's a 1440p IPS panel. It is lower contrast so might not be so good for movies, but it is accurate after calibration so good for photos and video processing. Like the QNIX below, its achilles heel is brightness uniformity.
• Nixeus VUE27D. A decent monitor with good picture quality but the Monoprice IPS-Glass Panel Pro is just a little more and has more inputs and this is DisplayPort only, so won't work for devices (like the Raspberry Pi) which have HDMI.
• QNIX QX2710. These are at the leading edge of Korean imports. When the first 2440p monitors with IPS came out, you could get these for cheap. $350 on eBay. The main issue is warranty and who fixes it. It is an AVHA panel (Advanced Hyper Viewing Angle) from AUO. They get the cost down mainly by having a less uniform brightness and at 33ms, it is slow for a gamer. So there is a real tradeoff • ASUS Rog Swift pg278q. This is a 2440p monitor but has up to 144Hertz Gsync targeted at gamers. It is$800 and uses 8-bit TN.

TNTCentral has the most comprehensive reviews as they are a dedicated site:

• BenQ BL3200PT. It is $1100 and is a little unusual, you get a 1440p display in a 32" panel. Excellent performance, but more importantly you get much more real estate and the pixels are larger. So a good compromise. Probably better than 27" 1440p. • Asus ROG Swift PG278Q. This is the first "gaming" 1440p monitor and is ultra low lag. It only has DisplayPort as that is the only port that can drive a WQHD display at 144 Hz. To get to that speed it uses a AU Optronics TN panel. After calibration it has excellent accuracy and the combination of G-Sync (so the card can control refresh rates) and fast rates makes this really the gamer panel of choice. • Eizo EV2736W. A higher monitor, this is 27" WQHD IPS panel. It costs a bit more, but has more features (although it lacks an HDMI connection) at$800.
• Dell U2713HM. This is probably the monitor to beat in this price category. It has good color accuracy, uniformity and contrast. The main issue is the price.
• AOC q2770Pqu. This panel is in the same class as the Dell U2713HM (LG AH-IPS) and the ASUS PB27Q (Samsung PLS), the Acer  B27HUL (LG IPS), the Benq 2710PT (AU Optronic AVHA) so this is a good mini-review of mid-ranged panels. It has excellent color accuracy and good contrast and decent uniformity.
• ASUS PB278Q. This was an OK monitor, the main complaint was color accuracy, although contract and uniformity were good.
• QNIX QX2710 LED Evolution II DPmulti Evo10. This is part of the low-cost panel vendors like Catleap but this is a 10-bit/color effective using an 8-bit panel and FRC (frame rate control) with DisplayPort. It uses the AU Optronic AVHA like the Benq 2710PT and LED backlight. It is a pretty vanilla display and the advanced features (overclocking) don't seem to work.
• Monoprice IPS Zero-G. This is a lower end monitor and lower performance too which Anandtech also found (they liked the higher end IPS-Glass better).

Flatpanelshd.com also has a good summary of recommendations, but they haven't done a review in 7 months for monitors, so they are a little stale.

• Dell U2713HM. Even though this thing is two years old, people still like it. Same as Anandtech and TNTCentral, it has good uniformity, contrast and color both pre and post calibration.

Looking through Amazon and their monitor displays here is what is selling in popularity order and also noting ratings. We are just looking at 1440p monitors now. 1080p are much cheaper at $280-300:\ • Dell U2713HM. This is outselling the ASUS, but has a lower rating and a higher price, so people are valuing the warranty and the name for 4/5. Most of the complaints from last year when there was a problem with the A00 revision, so beware of old monitors. • ASUS PB278Q. It is amazing to see half of the top 10 monitors are from ASUS. This one has a higher rating 4.3/5. Most of the complaints are about dead monitors, so there isn't really support for it. • Apple Thunderbolt Display. Amazing it is no the list at$949 🙂 Supposed to be the same panel as the Dell.

I skimmed these sources as they don't really do in depth testing.
Wirecutter says the Dell is first, but you have to look at the price difference to really tell.

• Dell U2713HM. There are lots of Dell models, but the Wirecutter likes this one. The main issue is reliability and Dell service. I like to check Amazon reviews to see what people think and it is 4/5. But it has the key features. It is an IPS monitor, so it is bright and it is 1440p. It uses LED lighting so it is light and has constant brightness across the screen. They do have a perfect pixel guarantee and a three year warranty. They are a little spendy at $600, but the warranty might be worth it.$2800 currently.
• ASUS PB27Q. This has slightly worse reviews from Wirecutter's view than the Dell, but Amazon review like it better and it is $528. • Nixeus Vue 27. This has DVI inputs and is cheaper and is US based. PC Magazine also does reviews and in going back through its list by most recent we see, here are their editor choices • Acer H276HL. Probably the best of the 1080p HD monitors. It is just$250, it's a great budget monitor. It uses IPS. They dont' calibrate the monitors they test, so it is hard to really judge image quality.
• ASUS PB287Q. This is a low cost UltraHD monitor if you want to be on the bleeding edge and has decent viewing angle even though it uses the older TN technology. $650. • Acer K272HUL.$450 gets you a 1440p monitor with IPS