MECHANICS
The chainsaw controller is setup as if someone snapped a Gamecube controller into a 90 degree angle. This means you're not tilting the control stick directly forward to go straight and the c-stick controls feel like they've been assigned to a new axis. It also means that you can comfortably rest the controller on your leg and mash the A-button for those events that call for that. The analog stick feels slightly larger than a regular gamecube controller (it is). Aiming with the L-button [Left trigger] depressed feels awkward as I have to reposition my hands on the controller. Doing the snap pivot aiming (see this
video) is made difficult with this controller.
The buttons. The A-button has a little more depression. The problem I have with the controller is the R-button: it is too stiff. The button is not pleasant to hold down and this is probably why I sometimes accidently un-aim if I hold my gun out for too long. Also, the triggers do not have the ability to slightly depress so keep that in mind if you are planning to play other games.
I have to pick it up again but the controller's rumble didn't feel that powerful when I was playing. Only when I specifically went to shoot handcannon rounds with the controller outstretched in one hand (as if pointing a gun) did I witness the power.
So with the exception of performing snapturns and aiming with the knife the controller works out okay. It does bring me back to that feeling in the demo where you were initially figuring out how to react, what to do -- not being fully confident yet.
I think this controller would be interesting to share Mario Party 7 style.