There's no "best", there's only "best for the job". Consider the kind of music you want to play on it, see what kind of hollowbodies would be good for that, and go from there. Without wanting to sound like too much of a fanboy, I have yet to play a hollowbody Guild that was a lemon.
As to what I think of Gretsches - vintage Gretsches are, especially compared to Guilds, usually too expensive for what they are, and fairly bad guitars from a construction/quality control point of view.
I have gotten vintage Guilds off the internet without being able to play them, but I'd never do that with a vintage Gretsch, unless it's too cheap to pass up. If you find a nice one and are willing to invest some money to make it play, they can be killer sounding, well-playing guitars - but it will probably cost money, and more than a nice older Guild at that.
New Gretsches - steer clear of the pre-2003 (pre-Fender involvement) ones, because most of them are overbuilt and heavy, lifeless guitars with sub-par pickups and electronics. When Fender got involved, the Gretsch lineup starting resembling the "golden era" Gretsch guitars a lot more, and they're really nice guitars.
