I'm on Hardware version 0002; I flashed up from a Froyo rom (Fresh) with no wipe; no issues noted. Phone booted, I downloaded the patch, but when I tried to apply it via the Fresh Updater I encountered the triangle/exclamation mark. I booted the device normal, flashed Amon RA, and applied the patch zip. Booted up fine.
Hard to say if GB has any benefits over Froyo at this point; you do LOSE some useful functionality with this beta (e.g. the ability to toggle radios in the notification bar), but at least we're up to par with other Android phones.
we just gotta wait for Jschisurf to port the toggle over to gingerbread (or any other dev, but since he was the original dev to create this mod on our evo's running sense, i'm sure he'll do it once the official OTA releases).