I just upgraded to WordPress 2.2.3. I always wait for the one click install to be available. It was, so I clicked. I also always write a test post just to make sure things are truly ok. 
Quick reactions:
- I like the link to preview instead of the having the post displayed in a box below every time I write a blog post!
- L’s Linky Love is working.
- Kontera Control is working.
- Hide Sponsored Categories is working.
- Adsense deluxe is working.
- I haven’t checked anything else!