Mmm, I should have looked at this pet more carefully, I like his skill set! Gonna have to get myself a rare one and level him
He's got Alpha Strike, and you know you'll have to use it while you wait on Call Darkness/Nocturnal Strike cooldowns (assuming you're going with these abilities, which sounds best to me). So more Speed would be a plus, but on the other hand, being a Flyer, he most likely won't need it as long as he's over half HP. Mmm.. hard to decide which Breed would be best!
8/18 would get my vote I think, 289 speed at 25, so above average speed even once he's been taken below half hp, and 289 power for a little more firepower... Or 5/15 if you want to ensure you're (almost) always going first.