i originally wanted a hard drive based dv cam as well. however, if quality is a concern, it may sound weird, but dv tapes are still the way to go.
using a dvd or hdd typically means that the dv cam uses some sort of compression to fit the audio and video on there. dv cams that utilize tapes write raw video to the tape, to which you can do anything with.
also, hdd based dv cams are said to have a slight hum in the video, from the hdd spinning during fliming.
having a tape based dv cam (we have the canon optura 60) i can say that the quality is amazing, however capturing the video is a chore. i have about 8 tapes sitting in front of me waiting for me to begin the capture. 8 hours. . .
then i have to put them on a dvd or encode them.
i imagine hdd and dvd based cams would already be mpeg 2 or 4 video, so its just like video from a digital camera (altho most of those come in .mov format (quicktime))