Well a couple things I can think of...

1) The Mech advantage is more constant through the pull, while cantilevers' diminish the more they are applied.

2) The (front) cable stop for the v-brake is on the brake and thus is a bit more "tied to" the fork during flexing. The cable stop for a canti is above the headset. The canti cable stop flexes more during application of the brakes and is less "tied to" the fork.

I like Cantis. Just weighing out the options. I want what will work the best, and provide the best feel. I might just go with the modern Shimano BR550 cantis.