I don't hate him, but there are some things I dislike about him.
His arrogance. You'd think losing to Naruto, being side-stepped by Obito or having his sense of smell easily countered would stop him from bragging. Apparently not.
His tendency to act like a jerk to Shino. He was just as bad as he was to Naruto. Calling Shino a "freak", complaining about his faults, gets annoyed when Shino mentions that he should try his best as he missed the Sasuke mission even though he told Shino to do the exact same thing, tells Shino to quit nitpicking when he is the one actually doing it, says Shino talks too much about insects but he talks to Akamaru, tells Shino he should talk "like a normal person".
Now I'm certainly a huge fan of giant beasts and his two huge dog forms are awesome, but it's like "Hey, cool. A giant dog. What does it do? Oh, it spins." "Another giant dog. Surely an extra head means it does something new. No, it just spins." All his attacks end in spinning. It's repetitive and boring.
His pointless, attention-seeking comments. Is he supposed to be the character who's just there to voice what the reader's are thinking? If so, it's done well.