I've been using only iMovie for OS X because I don't have iMovie for OS 9, but as far as my experience is I haven't had dropped frames while importing video. When I've finished my movie and trasnferred it back on tape, everything is as smooth as when I first shot the footage. And I'm using the first version iMac DVSE (400Mhz, with RAM upgraded to 384, and I'm still using the original 13 Gig HD!).