AirPlay is just Apple’s version of DLNA, which most bluray players already support, and has free software for most devices you might have content on. As of Jan 2011 9000 devices are DLNA certified with 440 million estimated out in the field. And I don’t think those numbers include the fact that you can install DLNA on any computer. Now none of the DLNA software I’ve seen is as sexy as AirPlay, but that’s the Apple way, take something already out there, give it a cooler name and a sexier UI and trust a whole bunch of people to conveniently forget the previous version owned by somebody else.
The major difference I've seen so far being that AirPlay actually works. Seriously, I tried DLNA to the PS3 and to other computers, and on the rare occasion that the products that said they were DLNA compatible actually produced video, they were often choppy. Same hardware and network all around, replace the PS3 with an ATV, use iTunes, and it all worked perfectly from the first moment, not even a stutter. After my previous experience with various DLNA clients and servers, I was very impressed.
but that’s the Apple way, take something already out there, give it a cooler name and a sexier UI
True, true, and true. But add two: making it work seamlessly, and charging more. Like I always say, Apple is rarely the first to do something, but Apple is often the first to do it *right*.