I have both phones currently. Received a One X yesterday via Expansys. After 24 hours with the X, I miss the Note.
The X is a really really nice phone. Fast, great screen, well built, great looking, and sense is a joy to use. It's really a huge improvement if your coming from any phone with a smaller screen.
What I miss, is the screen size, and the battery life. There are times I wish the Note was a fuzz smaller, but the first thing I noticed while using the X is the small screen. Ha, who would have thought 4.7 was small. The battery life on the X isn't bad at all, but it's not Note like. I cant truly comment on battery life after 24 hours, but I feel the X will give me 12 hours, the Note is an easy 16.
About the speed. Things are zippy on the X, but I do notice sense does lag at times.
Again, I'm really impressed with the One X. It's an amazing phone. I just miss the Notes screen and worry free battery. And oddly, the Note feels better in my larger sized hands.
John