It varies from base to base. Quantico is a heck of a lot nicer and better kept than Edwards AFB (the base housing I lived in there had swamp coolers, walls that were crumbling, and my internet service managed to download at rates of 300-400 bytes/sec through the phone lines). Whidbey Island NAS is a heck of a lot prettier than Cannon AFB. And while I’ve only got 24 years in the USAF, I can’t say I’ve seen a lot of flower beds on USAF bases.
My experience with USAF bases is limited to the East Coast. I almost always stay at one if I can over a Navy or Army base, because they are nicer. As you said, it does depend on location. The Navy’s SSBN bases are very nice, and there are some great ocean side quarters at certain bases.
I’ve never been on a “nice” Army base, but I’m sure a few exist.
Perhaps we should start a forum on the best bases to visit ;-)