Well, they are both professional FCs. WKM is the old version of the A2. The A2 has been having a lot of problems of late where as the WKM is pretty tried and tested. With that said, I have been testing an A2 rig for the shop I work in conjunction with and I have been ragging this thing around. When I say ragging it I mean I have tried everything that I think could cause it to go astray and it has flown faultlessly since upgrading to the 2.3 firmware version. Still not 100% there yet but my confidence is slowly returning with the A2. If you are not in a rush then it would be worth waiting for the A2 to settle down a bit as it definitely flies better than the WKM