I got myself a Chromecast on the weekend, since they're finally available in stores in Australia, and I was mallratting around.
Setup was pretty easy, clear instructions on screen and set up on iPhone. Not having to use a remote control to enter WPA passphrase shouldn't be amazing, but it is.
User experience depends wildly on the app. I've tested so far with YouTube on iOS, Plex on iOS and Google Chrome on Mac to stream tabs and desktop, and figured I may as well write some thoughts down.
This is definitely one of the flagship use cases. Flicking things to the device is easy, and the "TV Queue" playlist was exposed in all the right places to make it obvious and easy to use.
There was little lag between selecting a video on my iPhone and playback starting. Quality was as good as the YouTube videos allowed, and there was no performance difference compared to any other wireless computer in my house.
There definitely seems to be some "beta" around the edges here, as Plex would often connect (or say it was connected), only to have playback fail to start. This was always fixed with a disconnect/reconnect, but it's fairly frequent, so definitely adds some friction.
On the flip side, being able to explore and filter your Plex library with a touch interface, rather than a shitty on-screen menu is a great bonus. PlexConnect on the Apple TV is one of the best remote-control interfaces, but even that is nowhere near as good as the iOS app. PlexConnect also suffers from a lot of stability issues too, at least for me, and frequently has issues with files over 4GB (like some higher-quality movie rips).
No real playback issues at all with the Chromecast. After testing with several 0.5 - 2GB TV episodes and a couple of movies over 4GB, there are very few issues with playback once it starts. I had one or two brief (~1 second) pauses in some large movie files, but not consistent or reproducible.
The biggest downside is having to unlock whatever mobile device you're using to control Chromecast in order to pause and/or scrub backwards and forwards. This is more frustrating in longer movies, where you'll often have to do the dis/connect shuffle to get control as well. I'm sure these issues will be ironed out over time though, as the Plex team are pretty active in development.
This wasn't something I played with a lot, as streaming a Chrome tab to my TV is not something I do a lot. It showed up, I guess, and the extension was easy to install/use to cast a tab.
Casting the entire screen is a little buried in the Google Chrome extension and, when you find it, is marked as experimental. It was about as laggy as wireless LAN remote desktop is, but had a LOT more latency, and is graphics only, no sound. A novelty only, or possibly useful for a very static presentation (although in that case I would suggest an online presentation tool and casting a single tab).
Generally I'm pretty happy with the Chromecast, mostly for the reliable performance with Plex, which is the biggest use of my TV. The YouTube features are nice, and show what's possible, so here's hoping more apps become available over time.
p.s. turns out I have a blog ... who knew?