They fit so nice. I'm 6' and have XL for the normal tees and L for the tall tees. The XL is a slim but tall fit, super nice. Like it's almost as long as an XXL tall tee from other companies. Think similar to jiberish. It comes down to about mid thigh on me, but it's not ridiculous (even my dad says it looks good on me, and he isn't a fan of super tall stuff).
The L tall tee IS longer than other companies' XXL tall tees, but is super nice and slim and fits like a regular shirt other than the length. It's about the same length as my XL saga jacket from last season.
Moral of the story: buy one. Amazing quality, fit, and they look rad too.