Getaway isn't as deep but man is it fun. Lots of orbit shots, really cool ball lock, The supercharger never gets old, and it has a functional stop light! I wouldn't mind having a demo man too (deeper game that isnt overly complex) , but I don't think I'll hunt one down like I did for the Getaway, even if I do love me some Huxley.
TLD;DR Cant go wrong with either.