My main gripe is with cantis with "smooth" posts (well, they're often knurled in some way..). Having all axles of adjustment loose at once tended to make me wish for a 3rd hand. Not that I know if I'd been able to get those fingers as well in close enough to be useful though....
If I'd had cantis with threaded posts I don't think I'd been that eager to switch to Vs. Never had an issue with the braking power as such, apart from during foul weather rides when my hands got cold enough to begin to lose strength.
Come to think of it, while I ran a max power with really low straddle cable setup, I was a bit worried about the main cable coming apart and the straddle cable hooking onto the tire. But that fear was manageable with frequent inspections