We're still evaluating Plesk for Windows, so I don't really know what is new and what isn't, except what I've read on the forum. For us, it looks like it's going to do quite nicely - a big driving factor is that we have access to very very good Windows people, but not so much Linux.
Some issues I've seen:
Running PHPMYADMIN causes the license key to reset and your key needs to be uploaded again (fix is in the troubleshooting forum)
Some folks have been having trouble with web mail (we won't be using web mail so that doesn't concern me too much)
There was mention of stats problems (specifically AWStats)
You should check out the troubleshooting forum so you can make a more informed decision.