Jlac I commend you on coming in here and asking a bunch of questions before buying...
IMHO I would buy the Uniden BC-246T. It's very compact, has alpha numeric display (meaning you can title each channel with a text name) so instead of having to remember who is 462.5675 and 462.5565 and so forth you can add names to each memory channel. Another thing I like about the 246T is the new feature called Dynamic memories. Up until the 246's creation all scanners worked in static memory banking. Meaning that there is a set number of memory channels per bank and you couldn't modify that number. Say you had a 200 memory channel scanner. That would mean you would typically have 10 banks of 20 channels each. Let me put it like this...
Let's say you want to seperate police and fire and ems by bank. So bank 1 would be Dallas PD which has 5 working channels, so in bank 1 you load all 5 of their channels. Then in Bank 2 you put Dallas FD which has 3 working channels, and so on. Well you've just WASTED all of those extra memory channels. What about 6 through 20 in bank one? and 24 through 40 in bank 2????
Dynamic memories allow you to specify how many channels you want per bank. So now you can create a 5 channel bank and 3 channel bank and 100 channel bank and so on. I think the Pro97 has something like that but from what I've read it's not the same thing, or its limited in ability.
The 246t also has Close-call which is the same thing as signal stalker II. It's like having an active frequency counter. Any RF signal near you (within usually 500 feet) is picked up you'll have the frequency displayed on your radio. The PRO-97 and the BC246T are in the same price range, they're the latest (non digital) trunktracking scanners. Both are about 220 dollars.
I guess if you don't mind having a slightly larger portable and need it soon, or can't order online then the PRO97 is the fastest way to go. I personally would still go with the Uniden.
You can look at pics and specs of it here:
http://www.bc246t.org/
http://www.uniden.com/productpop/00_productpop.cfm?prd_code=BC246T
http://www.rigpix.com/bearcat/bc246t.htm
Good luck on your research and hope you enjoy the hobby... If you're curious to hear digital trunking hop on over to my online scanner and you can listen in to the agencies in my area, link in the signature.