With chipped A adapters, you can get EXIF and SteadShot, so you'll lose both of those if you replace the mount. There's a couple of companies that do custom mount replacements (sans electronics, of course) and I considered going this way, but having a stabilized 35 lux and 90 cron when I'm caught in bad light without a tripod was too big a draw. That, and I want access to the other mounts that can be adapted to A. The R register is too long for anything else.