MonoTouch性能与Objective-C / Java相比

I'm in the process of developing a multiplatform game engine and am using MonoTouch to cover Android and iPhone. I'm really interested in the performance aspect of using MonoTouch for iOS and Android development, does anyone know what, if any, performance impact MonoTouch will have over developing using Java or Objective-C for their relevant platforms? I ask this specificlaly from a game developers perspective, so things like drawing code and such really worry me. From what I've seen mono apps run fine, but say you made a game in the level of Angry Birds (art work, sound, physics processing), would that run well enough through mono that you wouldn't be put at a significant disadvantage over using the native language of the platform?I'm in the process of developing a multiplatfor