You can request a specific building, but it's only a request, not a guarantee. You'd probably have better luck requesting a certain area, rather than a certain building, but depending upon what's available that day and how many people ahead of you have requested the same thing, you still may or may not get it.
"Best" is really relative - it all depends upon what you like. Some people like to be in a more quiet, away from all the hustle & bustle area - that would be the Paddocks at SSR - it's the newest section that's opened, and has it's own quiet pool and is situated around a lake. Some people like to be in the middle of the action - near the main pool, etc., and that would be the Springs area at SSR. There's also the Congress Park area that's somewhat removed from the main area, and is directly across from the Marketplace area of Downtown Disney, it has it's own quiet pool as well. I'm not sure when the area on the golf course will be open, but it might be by the time of your trip. I'm guessing that it will be a pretty popular section. Does anybody know when it's supposed to be finished?
I think most of the negative you'll read about SSR centers around a fear that the larger number of SSR owners will overwhelm the system, making it more difficult to get reservations at the smaller resorts on short notice, and not so much complaints about the resort itself. It's a very lovely place, with upscale furnishings, nice pools and a spa, close to all the activities of Downtown Disney, and it will soon have it's own table service restaurant at the Turf Club. Don't worry about the accommodations. You'll have a great time - both at WDW and SSR!