Simple Tags ran fine with RC1, but if I left simple tags activated before I upgrade to RC2, it completely screws up the site and I have to downgrade to RC1 to or 2.3.3 to fix it. Granted, this is more Simple Tags' problem then wordpress' but just thought I'd throw that out there.
RSS widget: AWESOME how it works now, but, at least on my website, there was no break between the title of the syndicated post and the date, so it looked something like "TitleDate"
"Something Interesting HappenMarch 28th 2008
You'll never believe what happened on blah blah blah"
I added an extra
between the date and the content and its much better now.