I finished it last week.
The maps aren't that difficult to read... I dunno...
Anyways, I'll agree with you in some areas...
Ending was a disappointment, all that build up... woo... it is buggy as well, but no buggier than the others... in fact, I'd say a LOT smoother than the original GTA3. The flying engine can be a frustration, but if you fool with it some it's really as effective as it can get.
However, I disagree with your assessment that Vice City was better. I detested a lot of VC... the city pretty much sucked, the gangs were far too aggressive (you get shot any time you go in any of their areas), and a lot of things seemed half complete (the city itself included).
With San Andreas, a lot of the map isn't even used much in the main storyline, which really opens it up... it all becomes useful later when looking for stuff and just exploring. Moreover, each city has a distinct feel to it, similar to the original 3 districts in Liberty City.
One thing that VC did better was use of the property system. San Andreas properties are pretty much useless. Most of the ones that make money don't make much, and most of the housing doesn't have a garage (the entire point of the houses, if you ask me... there's so many of them, having a nearby save point isn't an issue).
The skill system ROCKS. The weapons are a huge step above the other two. The variety of vehicles is amazing. The motorcycles in particular are a ton better than VC... there's also an airliner that's pretty sweet for novelty (but it's a biatch to fly!).
For those who haven't finished the game, get a Desert Eagle and max out your skill (you can do this quickly by shooting a tire over and over)... it's a bit expensive, but one shot kills with an easy-to-carry weapon rock. In fact, I used it almost exclusively in the last mission...
Anyways, San Andreas is a good step up, IMO.
The best feature of the game, 2 player mode. There's a distance restriction (you're both on the main screen, no split), and you can't go inside buildings, but even with those lackings it's still amazing. Each person starts out with the ammo/loadout of the 1p. Tag team destruction! Your wanted level also decreases a little faster, so that, even with 2 stars, you can stay out of the cops way for a little while and get rid of it without having to find the remover thingys (you can't use the Pay 'N Spray)...
For those who didn't know that feature existed, here's a map of the locations...
http://gtadomain.gtagaming.com/2pmap.html
I stumbled on one in Los Santos one day and wanted to try it, later I was roving around Redsands and had my brother join me.
Anyways, yeah, definitely $50 well spent. Takes quite awhile to finish the story and I only have about 80% done, so I've got plenty of work ahead of me.