I switched to WP 2.1 a week ago, played around with it a bit and then went live. Here are some of my thoughts about the new version:
1. Auto-save posts. I've lost a few posts in older WP versions because there was no autosave and I never found an autosave plugin.
2. I like the toggle tabs between visual editor and code editor.
3. In the future I plan to use the feature that lets me set a particular page as the home page without moving WP into a subdirectory.
Me no likes:
1. Feed is cut off at the <--MORE--> tag without an option to override. I don't so much mind that it's cut off there because I use the More tag infrequently (1/5 posts) but it confuses some of my subscribers.
I haven't noticed any other new features yet, nor have I had any problems.
Thanks to everyone who worked hard to produce 2.1.