The Einstein 640ws has been getting a lot of attention lately, and for good reason.
It has a unique LCD display that handles your controls, and it's own proprietary wireless trigger system. It can maintain color accuracy across it's entire power range, and has the ability to produce a surprisingly short flash duration.
Paul C. Buff makes a nice variety of accessories for the Einstein, making it flexible enough to be used in any photographic situation.
In this video, I go in depth into the menu system, and includes some shots taken with the Einstein, at the end.