A pet does not really help in instances, you usually have a squad, so a little bit more damage makes no difference. An owl can fly, so it is the only option in pk. The owl bugs a lot, gets stuck on everything, so drake is easier to play with on the ground. Drake has more hp and deals less dmg. A good veno uses his pet for it's skills, not really dmg, so drake woudl be a better pet if it could fly:)