The 200 isn't shorter, but it is more compact: the body is narrower than that of a 300 (which is huge) and will therefore also be slightly lighter in weight. What's more, it doesn't have the classic triple coil ATK humbucker, but instead has a quadcoil humbucker with different switching from the regular ATK models (on the ATK300 there is a single coil setting with a phantom coil to reduce hum, the ATK200 is always full-humbucking). On the plus side, the pickup of the ATK200 has regular MM dimensions and can be easily replaced by any type of Music Man-like pickup, making it much easier to mod than the other ATK's.