Who do you prefer?

Spyro.

None of them

Paarthurnaax, obviously!
He's a lot more open-minded, has a great deal of self-control and is just a likable character in general. He's the sort of guy you become attached to easily. Alduin, on the other hand ... He's a very straightforward dragon. He's got a job to fulfill - ending the world - and will stop at nothing to complete that goal.

What kind of question is that?

Both evil in my opinion, I think paarthurnaax just want to use you as a pawn to kill Alduin so he can rule over the dragons. If you know what his name means then you'll know what im talking about.

Odahviing Is the only dragon I trust and love those another just have to go