Hi
I've the same issue as you guys - I bought a pair of Wireless Beats... awesome sound but when I watch a movie, the audio is slightly out of synch with the video which is really disturbing to say the least. I don't think the issue is the headphones, it could be due to the Bluetooth version (currently 4.0) in the iPhone and iPad (currently own an iPad air) so it seems likely to be a software issue.
I recently asked a friend to pair my bluetooth headphones with his Blackberry mobile and to my surprise there were no issues at all, the audio and video completely worked together, no lag.
After this test we can conclude there's nothing wrong with these Headphones and I'd like Apple support to try out and test and see the results themselves on other mobiles - perhaps there's a software update in the pipeline?
Thanks.