There are so many opinions on this topic that I won't bother to summarize them. The PSR500 and 600, from what I have been reading, seem to have better digital audio recovery than the BCD396/996 (it's rather early to tell if the new firmware release has solved any of these issues - some have had very good luck with it, some seem to have found some bugs...), however if you are close to a major area, the PSRs tend to overload easier than the Unidens. Many folks like the PRO-96 and 2096 - however there are some things you cannot do with those that the Unidens and GREs can - namely, running a PC program to log and record, as well as control the scanner. Those 2 cannot cover the milair band out of the box, and even if you use Win96 to open them up, the sensitivity tends to vary widely from unit to unit.
I like my 396. I am not quite so critical of the audio as some of these others, as one must keep in mind that these aren't designed to be, or intended to be, replacements for Motorola equipment. There's only so much you can push out of that little speaker, after all. I get only a little overloading - only when I'm in the Woodlawn area, with all those blasted 800 mhz and MW towers, just about anything is going to squawk now and again.
There are a couple of newer digitals coming on the market in the next couple of months - the jury is still very much out on these.
You'll have to be a bit more specific about what you are looking for in a digital scanner. I know Troymail has both the GRE and Uniden units, and I'm sure he will jump in at some point. Remember as I understand it, right now AA is not using digital, except on some private calls (I-Call). However there is so much digital that surrounds us (and eventually it's expected AA will make the switch) that making the move now is the right call.
As for getting all the IDs, there are many applications now that can connect to the database and download data into the edtor for the scanner. You need a premium subscription, of course, but that's inexpensive. There are lots of ways to get files if you are too cheap <ahem> to get a subscription. To a certain extent, that's dependent on what scanner you get, and what software you are using. For some applications, that's an important consideration.
73 Mike