First things first. Jet mode is the worst of the three modes. Fat, chunky, and obvious arms. Same for Skydive, and probably Air Raid. At least he has front landing gear.

However, bot mode is quite awesome, well articulated and balanced, main drawback is no actual feet.

Combined mode works very well for foot mode, however arm mode has a couple of issues - his hands don't quite reach to the tabs on his back, so just hang there loose, and the tailfin blocks some weapons, like Powerglide, from fitting into the combiner hand.