MPEG-2 is actually not that bad of a compression format. I would still probably lean to the MiniDV because of the ease of tapes. HD based cams CAN have comprable quality, but it is camera dependent. MiniDV is a much more universal format.
From Wikipedia...
"Video compression
DV uses DCT intraframe compression at a fixed bitrate of 25 megabits per second (25.146 Mbit/s), which, when added to the sound data (1.536 Mbit/s), the subcode data, error detection, and error correction (approx 8.7 Mbit/s) amounts in all to roughly 36 megabits per second (approx 35.382 Mbit/s). At equal bitrates, DV performs somewhat better than the older MJPEG codec, and is comparable to intraframe MPEG-2. (Note that many MPEG-2 encoders for real-time acquisition applications only use intraframe compression [I-frames only], but not interframe compression [P and B frames].) DCT compression is lossy, and sometimes suffers from artifacting around small or complex objects such as text. The DCT compression has been specially adapted for storage onto tape. The image is divided into macroblocks, each consisting of 4 luminance DCT blocks and 1 chrominance DCT block. Furthermore 6 macroblocks, selected at positions far away from each other in the image, are coded into a fixed amount of bits. Finally, the information of each compressed macroblock is stored as much as possible into one sync-block on tape. All this makes it possible to search video on tape at high speeds, both forward and reverse, as well as to correct very well faulty sync blocks"