Pretty sure some people had issues with non-Techart adapter. I suppose it really depends on the size and shape of the adapter you use, and while some other third party adapter will fit wonderfully, others won't.
Excessive battery drainage hasn't been a problem for me.
I always switch the camera off though right after taking pictures.
Also, I use a battery grip with wireless remote control.
That comes in very handy when a heavy lens is attached to a tripod and the TechArt Pro Adapter needs to move the camera.
As you can see from the link above, I only had success after the adapter was on the camera for awhile.
IIRC I also had Bluetooth enabled on my iPad3.
YMMV.
Please let us know if this procedure works for you or not.
I had to keep at it until it finally worked.
It worked just fine. I left the adapter on the camera because that's all i use for now. I don't want to take it off and put it back on all the time. Updating the firmware took a while though. Thanks