FYI, I spent the last better part of 1 1/2 months, and finally unlocked him today. I did this because my 5 year-old son wanted to borrow him in the challenges.
Long story short, he unlocks at 4*, he's not very strong. Already have him to gear level VII, almost VIII, power level sitting at 3434 currently.
Moral of the story: He's great to let your 5 year-old son borrow. His sound FX are the coolest in the game (in my opinion), he's flashy with his four lightsabers, but he's not viable at 4*. He won't lead your droid team to victory after all these years. He's simply, cool to see in the roster.
I'm sure at 7* he's a monster, but getting him there...well...the rest of your roster will have to suffer for months on end.
As he stands today: