OK, here are some great tips I've found. In random order:
- Vuescan for the Mac actually works well, but has glitches. The main issue is that sometimes it gets the colors all wrong even though the prescan looks good. The solution is to restart you Mac and then the colors are right.
- Vuescan also hangs if the little swinging door on the Minolta Dimage 5400 gets stuck open. It hands on the open screen. The solution is that there is a little hole where you put a paper clip in to manually push the door closed. Make sure it is closed before you start Vuescan.