As to whether Flip video recorders work with mac, have no fear. Everything works fine on my Mac. Even the FlipShare movie editing software works fine (contrary to early test reports) My only gripe is that the newest update to the FlipShare software doesn't work on my legacy PowerPC chip Macintosh. You must have the newer Intel processor Macintosh to use the latest and greatest Flip software.
Unfortunately there doesn't seem to be a very helpful answer here. There's a suggestion that mino has "connection problems", which may or may not include "ultra". I'm not sure if or why there would be any difference if the software is the same. My general understanding from searching the web on this topic is that at least the 2d generation flips *should* work normally with late version macs (hardware & OS), but that their movie editing functions are not mac compatible. A suggestion above is that iMovie might render that less significant.
Thx for the update. We now agree the Flip works just fine w/the Mac, and especially iMovie. We made a bunch of quite amateurish uploads on a fun site that shows how this looks. See www.mytripjournal.com/beartrek10