I went from crashing 5-10 times a day to only 2 or 3 times since the update, and one of the times it crashed was because I was in the middle of switching tabs or something fancy when I got a phone call and it bugged out.
I can't believe the crap we put up with in 1.0. Safari used to crash 20-30 times a day for me.
However, I did have an odd keyboard issue with 2.2.1. In Safari typing into a text box, the floating characters that pop up when you type were coming up sideways where they would be located if the iPhone was being help horizontally. It was pretty weird. I think I might start a post about it with some screenshots I have.
Also, I used the "Text Message" button in the contacts app, which I hardly actually use, to text my fiance and it somehow deleted her entire conversation history, which majorly blows.