Hi8 is analog, and DV is digital. Both camcorders can output recoders to PC with different interface.
For Hi8, you need a video capture card installed on your PC. And for DV, you need 1394 (Sony calls i.LINK) card on the PC.
You need software & CD/DVD burner to burn your captured movie clip on VCD or DVD.
Hi8 can also use 8mm tape, but DV use DV tape only.