You can get Brain in both NECA 7" and 12" versions which are the exactly the same in every way other than their size. I chose to get the smaller one as I also own the 6" NECA versions of Poker Player,Gizmo (he's 4") and Spike which you can get in individual blister packs or buy them all together in a window box pack. The (Gizmo, Spike and Poker Player)) box packaging is a bit easier to take the Gremlins out without wrecking the packaging.
Brain is the best of all of them though with a sensational paint job showing veins, muscles, scales and everything in sensational detail. He also comes with glasses that the lenses actually work. The arms on the glasses are bent to fit his head. He is wearing a black jacket which slightly moves but you can't take off. Likewise you can't remove his blue t-shirt. His hands rotate, as do his arms at both the elbows and shoulders. His legs move and unlike the other Gremlin figures, his feet are flat so he stands upright easily. His head moves up and down and side to side meaning you can position his head at many different angles.
Brain also comes with the book History of Civilization (it doesn't open). He also has a beaker flask thing with green liquid (it's solid) in it.
The detail on Brain is amazing, it is one of the best figures I own. I've uploaded a few photos in the customer images part of this page, check them out and see for yourself.