For my part, I still think his turn to the Dark Side was a little abrupt. Yes, I knew it was coming, so it wasn't a surprise when it did. I can't help thinking, though, that if I didn't already know he was going to turn, I would have been sitting in my seat wondering, "What the...?" when he does turn on Mace. I understand all his reasons for turning to the Dark Side, they are all valid reasons, but I think since we're so immersed in the setting and story, a lot of us are content to "connect the dots" and feel okay about it. Myself included, I'm willing to let it slide because I know it's a necessary part of the story, even though I'm a little dissatisfied with it.
But here's my real issue: so Anakin butchers the village of Sand People, he slaughters a group of little kids in the Jedi Temple, he helps orchestrate the slaughter of Jedi throughout the galaxy and helps the Emperor rule the galaxy... and then at the end of Return of the Jedi, he finally kills the Emperor, like all self-respecting Sith Apprentices are taught to do... and BAM he's back on the Light Side of the Force again? All is forgiven, buddy, welcome back? Small comfort to the hundreds he helped kill that he finally comes around and does what he should have done a couple decades earlier. It still seemed like a self-serving action to me anyway.
All in all, though, I felt this was the best of the 3 prequels. The light-saber battles alone were worth the price of my ticket. (Okay, granted, my work paid for the whole studio to go see the show opening day, so I didn't actually spend any of my own money. But it was worth my company's money to send me to the show!)