Re: Airplay does it how?
Airplay certainly seems to work pretty well but my experience is that it only works well with an Apple TV. I may be wrong but most Airplay devices take audio only and only the Apple TV does audio/video.
We're big fans of it in our house. I can beam pretty much anything from the wife's iPad or the phones and it does switch off the screen on the ipad so that you don't see two images.
I'm constantly surprised that Apple doesn't push it more publicly. It's an open format so Apple don't require any fee for implementation (that I can see, correct me if I'm wrong). Most iPhone owners seem unaware of it but I've found it very handy on numerous occasions. Simple and it works.
Oh and it does indeed need Wi-fi but there have been persistant suggestion that it was going to also start using Bluetooth in tandem to allow for more features/controls. No sign of that though. Never had any issue streaming to it. Buffers nicely so video doesn't hang (for locally stored content; external will depend on the broadband connection)
DIAL. Well that seems to be pretty poor. Requires the TV to load more software. can't see that working. I have Airplay and DNLA. No need for any more.