This page lists the issues blocking zd1211rw moving to the mac80211 stack. Some of these may already be resolved, they just need to be checked.
In the softmac driver, we temporarily disable TX while updating preamble mode and basic rates. This is not possible to do in mac80211 at the moment.
In the softmac driver, we program the basic rates for RTS/CTS based on the association info. Need a similar system in mac80211.
Ulrich has greatly improved the zd1211rw 802.11 error statistics. This code needs moving over to the mac80211 driver after figuring out how mac80211 does this.
We have happy ARM and SPARC64 users. To my knowledge, mac80211 has not been tested there.