Firewire transfer is fine for the Digital8 and DV tapes since it supports their native video format. (It is not optimum for analog tapes.)
For the Video8, Hi8, and Digital8 tapes a Sony GV-D800, or GV-D200, or higher end Digital8 camcorder will give you firewire output. Are your digital tapes MiniDV? If so they can be played in almost any MiniDV camcorder and it will provide Firewire output as well, or a Sony GV-D200 or -D1000.
Be sure your MAC can do Firewire in the flavor used by the GV-D and camcorders. (More recent MACs might have an issue with this, but I am not a MAC person.)