the "all-in-one" factor is the ultimate seller for this box IMO. It is so nice to have such a compact box for your rig. I've used the UA-5 for a long time, but that thing is still a little bigger and you will always have some battery hanging off of it, at risk to be unplugged for whatever reason.
The other week, some friends asked me to check out their friends reggae band. Not knowing if they were gonna suck, I brought the rig just in case (at853rx > ACM 660). It comfortably rested with me in a booth while we observed the first set and ate. Set break comes, I ask permission, and I'm flying hypers DFC for a fun second set. The band loved the recording. That is what taping is all about.
Yes it is limited to 16-bit. For the winter/indoor season, it is all I need. The 24-bit advantage for indoor PA shows is so minimal IMO. I would prefer 24-bit for pure acoustic acts, but you will still walk away with a nice recording, no doubt. I remember Doug saying a 24-bit mod to the 660 would be POSSIBLE, but somewhat tedious.
If I get approved for Lasik, I MIGHT have to sell, but I'll come back with a WCM unless Doug or Busman comes out with something similiar size and 24-bit (mod Fostex FR-2LE).