I know most of you probably don't want to hear any more about this chip, but I recently fixed quite a few long standing issues.
It's not perfect yet, but it improves scanning/reliable reconnect, incoming frames missed in powersave, ping times, and rate selection.
Here's the patch set: https://github.com/fifteenhex/xradio/pull/12
Edit: rebased from karabek: https://github.com/dbeinder/xradio/commits/karabek_rebase
And some important comments about powersave: https://github.com/fifteenh