6x7 negs/trannies are 400% bigger than 35mm; in the 645 format, a little smaller, but still a whopping improvement. At printing, there will be no discernible difference, save only for any faults introduced by you e.g. exposure errors, focusing off, etc.

There is an endemic quality of imaging at for either of the MF sizes (including 6x6 and slight variations) and print quality will be uniformly excellent, in terms of viewing to whatever size you desire (currently I'm printing at 81x61cm).