Omne has an interesting transformation sequence which at first looks confusing, but after you have gotten through it once, you probably won't need the instructions again. To be honest, I'm still trying to figure out the magic behind one of the crucial step, which I was reminded was necessary in order to bring the cockpit down. (kudos to Penguin One for sending me the instruction video to make my shoot easier).
Omne also has that interesting feature with the mini Bumblebee and Blaster. They are not removable and yes, they are really really small. So whoever painted them did a pretty good job.
He spots some ab crunch articulation too and as pointed out by godotislate, some pretty good finger articulation.
To be fair, Klaatu definitely has its own interesting accessories (e.g traction beam, spray can) which ups the 'play' factor and frankly, the figure grew on me after a few handlings.
So which one is THE one? I'm still deciding myself LOL.