The first time I saw Will Hines perform was when he was on the team Monkeydick. I think he's one of the smartest improvisors out there. He's amazing at playing characters that are grounded in scenes while performing the game of the scene spot on, along with the game of the character (which is sometimes the same thing). He's also one of those guys that is loaded with knowledge and trivia, like he would know who invented post-its.

I can't remember which team I saw Chris Gethard perform on first but I remember him, about to jump off the back line like it was on fire. He had so much energy and looked like he was having the time of his life. Gethard takes a lot of physical risks (which is my favorite kind of comedy to watch) and can justify just about anything. I also love it when he plays a scene as just himself responding. It's like you're watching everything in the moment as it should be.

I consider both Will and Gethard to be respected, knowledged, bad-ass improvisors and teachers.

Will's bio on UCB.
Gethard's bio on UCB.

Go read Will's one on one with Gethard.