How does Exp Share work in the Pokemon games?

I mean, I know how it works. I just want to know some of the finer details. For example, I have a level 100 Charizard in the front of my party, and a level 52 Venusaur holding the Exp Share. Since Charizard can't gain anymore experience, this means that Venusaur will gain all the experience Charizard earns in battle. My question is, will Venusaur also gain all the EVs (attack, defense, speed, etc.)? And if so, is there any down side to training Venusaur in this manner?