I agree that it can all depend on just what you are looking for.
We really lucked out, and were placed in a top-floor (what I called 'penthouse') unit in Cascades. Which is the newest section!
I know there was a GREAT post on all of this quite a while back.
Cascades is the newest, has the feel of an upscale condo. I agree with the last poster that it has a really great pool!
Lakes is next. Is also supposed to be nice.
Fountains-II has more of the feel of Villas, where you can step directly out into a nice shady area, nice playground for kids, etc.
I am not as sure about Palms and Spas - but they are older
Springs - I have heard needs renovation, you might want to avoid!
Courts is the oldest - but is supposed to have been renovated some, so it should be okay. (no pool or water views, no jacuzzis)
Vistana is GREAT! No matter where you are, you have access to the entire resort. And, unless you happen to get one of the few units that does need renonovation, you should have a great stay.
You can look up those unit numbers on their property map at the Starwood site. You will really have to ZOOM, but the numbers are indeed on there!
also you will notice that the units are color coded. So, your check-in day will probably help determine where you are placed. The Courts section, as you will notice, is all designated with the color for Saturday-Checkins.
You will want to contact their Diamond Lane a few weeks before your trip, to make any requests that you might have. EVERYONE always requests Cascades and Lakes, and they appear to automatically send out a response that states something like "there is no availability in Cascades and Lakes at this time". I don't think that really means anything. We got that too, and we got the BEST unit!
Also, I think that if you are an owner/exchange, your requests will probably have a little bit of precedence over renters, or people who have bid the online travel site. At least it sounds that way from what I have been reading.
Hope this helps, and have a great trip!