Same here... And I can definitely rule out some of those other factors (network interference, bandwidth, etc.). I come from a strong IT/networking background, my setup is ideal, and none of that in any way mitigates the issue.
I submitted this to their request form:
I try to use AirPlay to mirror my MBPr to my TV and it is a terrible experience. Any video playback is very choppy and laggy. This falls very short of Apple TV supposedly being a key component to the "Apple Ecosystem."
On the other hand, my iPhone 6 always performs AirPlay flawlessly. It seems like there is a big difference in the technical resources consumed to deliver video playback between the two different types of AirPlay. I wish OSX had something as reliable as iOS AirPlay.
My network is using a dedicated Xfinity modem set in bridge mode, leaving all routing to be managed by my Apple Time Capsule 3TB. I have no neighboring network interference, no environmental interference. The Apple TV is hard wired to the Time Capsule. My MBPr and iPhone use the Time Capsule's 5ghz frequency
I think Riis is on point:
I am in no way qualified to answer way the iphone gives better performance when it comes to mirroring with airplay, but I think it must be because of the different way the two platforms use airplay.
The iphone uses quicktime and streams "just" the video of your choice and does make a mirror of the iphone in the same sense.
The macbook makes a direct mirror onto the tv of everything on the macbooks screen. This might require a lot more from the computer compared to the iphone. Because the macbook is of course on all parameters much more powerful than the iphone.
It would be nice if Apple were able to make the macbook use airplay in the same, what seems to be a more efficient way, as the Iphone.