I live in Grenoble, and this is the best restaurant I could find so far. (Not much choice however...)
The people are really nice, and the food is good, even if you don't have much choice if you are vegan, both times I went there, I only had one option for hors-d'oeuvre and main dish.
You can have dinner outside, at the back of the restaurant, which is very nice when the weather is good (that happens often in grenoble)
Cons: few vegan options