Well with the market changing so quickly, our top choices of just two months ago (the the ASUS PB-27Q and the Benq 3200PT remain. The big problem is that the ultra nice Benq 3200PT has shot up in price from a decent $620 up to$750, so is pretty out of reach.
So what's a person to do? How about look at Tom's Hardware latest monitor update. It's really a transition time for monitors and graphics. The 4K monitors are not quite up to snuff yet (although the new iMac Retina sure looks nice!) so the trend is the so called QHD (2550x1440) monitors are in the mainstream now. We've been enjoying our iMac for five years now, so it is nice that the world is catching up. So if you need a monitor and can wait a year, it looks like next year is the sweet spot year to buy. But if not, here are the best choices:

• ASUS PB278Q. I don't know why Tom's Hardware didn't review this one. It is the number one seller on Amazon and has a 4.5/5 review. We have two at work and they are quite decent. (the Benq 3200PT is stellar). Needs calibration though. Amazon has these for $460 and Staples has it for the same price (but that includes a 5% rewards and also 2x points from Boa Rewards Mall). • Planar PXL2780MW. It competes with the ASUS PB27Q that we've been using to good effect around the office (just$426!) but it has a different technology for bonding the glass, so is much clearer. It's a 2550x1440 at 60 hertz, so just about a perfect general purpose thing. It's about $500 on Amazon and the main issue is quality control as quite a few folks have had problems with it. • ASUS ROQ Swift PG27Q. Well this is the monitor gamers have been waiting for QHD at 144 Hertz. It is a TN panel, but for speed, nothing can quite beat it. It uses nVidia gsync so the sync can be controlled by the monitor. It's the first big step from the 1080p 144Hertz ASUS we've had here for two years. A darn nice monitor too by the way. It's a good intermediate stop on the way to 4K gaming 🙂 • Overload Tempest X270OC. Then there is the thing that you can't buy. This is an off brand Korean system that can get to 120 Hertz by overlocking if you feel lucky. The gamers dream as it's an IPS monitor (not TN) and it is hacked. Too bad they aren't available. So looking at Amazon's highest rated 27" and above QHD displays we see: • QNIX Evoluition II. Amazon folks love it and TNTCentral says it is decent but it just drops frames above 60Hz. Cheap at$350!
• Viewsonic VP2770. This is a professional monitor at $650 that has good performance and should be compared with the Dell • Dell 2713M which is only$550 but has big reliability problems. It sure feels like the extra $100 is worth it given reviews on Amazon. • Benq 2710PT. TFTCentral likes this AHVA display and it competes well with IPS panels like the ASUS PB27Q. Amazon folks really like it. Reasonable$450