After a bit of closed beta testing, AllCast is available for everyone with an Android device in Google Play. AllCast made a splash several months back when it became the first app to unofficially support Chromecast streaming. That didn't last long, but now it's back with a slightly different feature set and a £3.05 price tag.
AllCast doesn't support Chromecast streaming right now. Instead noted Android developer Koush has designed AllCast to be an all-in-one AirPlay and DLNA streamer. It can stream videos and images stored locally on your device, but also anything you have saved in the cloud with Dropbox or Drive. You can cast video from the app itself, or with the Android sharing menu in the Gallery app.
As for device support, it's really only missing the Chromecast. AllCast can stream to Roku, Apple TV, Xbox, Google TV, Samsung/Panasonic smart TVs, and most other DLNA-capable devices. Koush says Chromecast support will be added whenever Google gets around to opening up the SDK to everyone. Unlike most of the Chromecast streaming apps already out, AllCast needs to keep the device awake to push local content over the network. Keep that in mind as it will likely increase battery usage.
The quality of the streaming will depend on your network speed and the device you're streaming to. Some users report issues getting video to work, though. The free version of AllCast is limited to 60 second video previews so you can see how it works for you. If you want to actually make use of the app, the £3.05 full version key is also in Google Play.