My favourite was K2SO, he was so silly, such a cool droid!
Though there was also the Bulletproof Monk guy and the PEW PEW PEW guy who were cool! I really enjoyed it, especially some of the spaceship vs spaceship combat scenes.
I loved it, and to be honest it was far better than I expected it to be. At first, I was kinda meh about the movie, but midway through I was absolutely hooked.