I don't have him yet, but its a tough call between sneak and rocket. Although I like Megas for sneak its fun to have a choice; and Dexter (who I chose for sneak) has horribly annoying dialogue. The only rocket nano I have so far is Professor Utonium who is just fine for dialogue - but again I like variety. I'll probably take sneak just because its a power I use for extended periods of time and I have to say I really want a mini-Mac following me around. That just seems awesome.