I've done several bridges with RB133c and got a pair of 411's sitting right here in 5GHz turbo. I get ~20mb throughput. I need to put a client PC on one and test from PC to PC, but from PC to RB411, send and receive test, I get 17mb down and 12mb up.
Doing more testing, but works fine so far. A level 3 license works fine for WDS bridges, I've got several in the field right now. On the bridging tho, I've set one as bridge, one as station WDS and had it work, when I changed to 10MHz channel from 5MHz, I lost association. I changed the client to bridge mode (dunno why, just tried it) and the two worked fine. Went back to 5MHz mode, lost association, changed the client back to station wds and it worked fine. This was with 2.9.4x. I haven't tinkered much with 3.3.