I think he did really well in all of them. The character he was playing was supposed to closely resemble a snake, he had the fluid movements, the hissing whisper to his voice, and I don't think there was ever a moment when he didn't have a wild look in his eyes. That's exactly how I pictured Voldemort.

However, knowing what I did from reading the books, it makes sense to me that he would get overlooked towards the end. (SPOILER)Voldemort is the main villain, but anyone who read the books would know that at the end he really wasn't all that powerful. I think he was overshadowed by Snape's revelation, which was the only reason I even went to see that movie.