Can't speak for the Epson, but I think the specs for both are very similar. I opted for the Canon simply because the local brick-n-mortar camera store carries them, and one of the experts there said she uses hers for scanning 6x7 negs and was happy with it.
I scan 6x7 Ilford Pan F at full resolution and get 358mp files with it.
The optical resolution is about the same. The two things I like better about the Epson are that it has a slightly higher film suspension height which reduces the chance of Newton Rings a bit and the Epson software is more user friendly in my opinion.
I have a Canon 9000F and am very pleased with the quality of the scans, but have nothing else to compare it to. I use Adobe Elements to play with the scans. I scan both 35mm (HP5+) and 6x7 (FP4+). After reading the other current thread (best film for scanning), I may try Delta again. I do not use the scans to make prints, rather to see if the negative is worth printing in the darkroom.
I have a V600 only so I can't give you a comparison suggestion. I did compare the published specs. But I can't seem to find the dMax rating for the Canon. The Epson is Optical Density: 3.4 Dmax. This is an important criteria as it represents the amount of light that can penetrate the negative. It gives some indication of how well the scanner will do in the denser parts of a negative in the shadow areas, an important requirement.
The Canon has a higher published resolution. But that doesn;t really tell the actual resolution that;s possible which is much much lower on the Epson so I would guess is similar with the Canon.