802.11r speeds up reauthentication. When a client moves between APs, it needs to re-authenticate. 802.11r provides preauthorized key caching to reduce the amount of protocol handshakes upon reauthentication.
The benefit is much more noticeable on ...
It only came out yesterday, but as I was upgrading for frag attack anyway (which was the patch immediately before this update), I decided to go to 200.10.
I haven't seen any issues but it's only been ~16 hrs for me.