Love both bands, but Dokken beats up on Ratt in every aspect of the game. More talent at each instrument and Don's vocals are tons better than Pearcy's. That's not a slam on Ratt, because I love them and still do, Dokken is just that much better (to me).
Interestingly enough, Juan Crocier, bassist for Ratt was the original bassist in Dokken, including their first album, before he left to play fulltime with Ratt (he had been playing with both at the same time for a while).