I don't think there is mass hate for Playtech's game catalogue at all. The hatred of Playtech is (quite rightly) born out of their willingness to turn a blind eye when one of their operators chooses to indulge in blatant rogue behaviour.
I myself would fully agree with what goatwack said in an earlier post. That quite a decent portion of their GAMES are excellent. Great Blue, Irish Luck, Marvel progressives, Penguin Vacation, Pink Panther, Sultan's Gold, Captain Treasure Pro - all great games with great win potential. And that's just the ones I can think of off the top of my head. They aren't exactly lacking in the music/sounds and aesthetics either.
BUT...
..that counts for very little when you factor in the fact that Playtech's reputation is more tainted than any other of the "big-name" software providers, except perhaps for Rival. Not much point in making great games if the player has to go through an entire casino directory trying to find one of the small handful of Playtech casinos that are legit, is there?
Basically, until Playtech decide to get their house ethics in order and police their casinos with the proper due diligence, they will remain a polarising figure within the industry.