As far as official Linux vs. cheapbytes, cheapbytes should be
fine. Buying official Linux will probably get you a modicum of
phone/e-mail support, but that's what we're for, right? :) On the other
hand, though, sending ~$50 bucks to your favorite Linux distributor at
some point probably isn't ever a bad thing either.
Other thoughts - well, just the usual stuff. Check the hardware
compatibility lists to make sure that at your stuff is supported, and so
on...
Matt