If you plan to use your PC then the MR-8 is your best value. If you want a stand alone unit with a lot of memory then it the VF-80 is better. Just be sure to shell out the extra $$ for the CDRW drive for the VF-80.
There are guys here doing that with nothing but an MR-8. There's also people who would find the VF-08 really limited. Clif is correct - you have to really "know" how you want to work. There are devices that can literally do everything in one unit, but you have to look beyond the VF-08 for that.
The MR-8 is the best unit for sharing tracks with a computer and, considering the options for inexpensive mastering software, it's a compelling solution for the price. Fostex tends to focus on recording and connectivity - Korg, Roland, and Tascam are more apt to cram effects and mastering tools into their boxes.