I've been looking at the XRGB3 also. Seems to be a solid unit, and there are tons of great reviews out there. Output quality is supposed to be not perfect, but absolutely fantastic.
They seem to be scarce. Another thing I've read (specifically in regard to the XRGB3) is that it does a poor job of handling certain PAL sources (flickering). That might "not" be cool for quite a few amiga games.
