I don't know about speed but battery life is terrible after updating to 5.0.1. It was great on 5.0.
Example: I locked my ipad with 56% battery left about 11PM Wed. night. I put it on the shelf and didn't touch it until about 6PM last night, and it was down to 30%. I played some games, checked email, and browsed the web and it was down to 17% when I was done using it at about 11 (didn't use constantly, just off and on). I wonder if it will be dead when I get home tonight.
I hope Apple fixes this quickly!! I like the gestures, but they aren't worth the decreased battery life. I would gladly revert back to 5.0