If it's anything like the current offering, mirroring via AirPlay to an Apple TV, it will be useless. There's a very noticeable lag. OK for presentations but as a a second monitor it would be dysfunctional unless they put in a lot of latency work. I hope they have.
I always love the use of the word "useless" on this site. "Ok for presentations" means it has an obvious use: presentations. How can that be useless? I'd agree it can be better, but it's obviously not without a use.
I specifically said useless for dual-screen setups in response to the comment I was replying to. I too find un-analytical praise or criticism annoying. I hope I wasn't doing it.
Just tried using airplay as a second display on my prev-gen Apple TV (black puck but 720p) and new MBA. Works fine but noticeable lag that makes mousing nasty. You probably don't want to use this for a "real" interactive display. Maybe the newer ATV would be faster, but I wouldn't expect too much.
I thought readers might appreciate a report from an actual end-to-end test. There's a huge usability difference between 15msec and 150msec latency. I observed the wrong end of that range.
FWIW, I think video stream buffering is the culprit rather than inherent channel latency.
Depending on the USB input device, that's not necessarily true at all. You could very easily find crappy USB input devices with greater latency than your ping to the news.ycombinator.com server, unless you're in Antarctica or something. There's at least one John Carmack twitter rant about ping to Europe being better than latency from some USB input device.
If you're a single router hop away from something the latency can be imperceptible. Whatever trouble is involved here isn't down to network latency.
