I like felt, does a good job lining the ceiling of my car.

The rule of thumb with two bikes at the same price point is to test each & go with the one that feels better to you. 650b is all the rage (& I must admit that I'm partial to them as an 'all-arounder' bike based on the reviews), but finding tubes & tires in bike shops may or may not be an issue. So I'd stick with the rule of thumb.