Hi, just to say I got a good deal on a Chromecast 2 at Maplins yesterday....£19....they also have them in Argos cheap this weekend.
The version 2 seems a lot better, you can download a free app to set it all up and it updates to the latest firmware. When casting the BT sports app to a large screen tv it works better than just the normal casting / Samsung smart view....as the chromecast takes over the streaming direct from your wifi....instead of wifi to mobile then wifi back to tv. You can adjust the settings down to 50hz within the app and that makes for a smoother picture. Not fully tested it yet but seems the best way to go for casting HD sports.
They also make a 4k Chromecast now, but it's expensive,,,,and as there isn't much streaming in 4k yet....probably not worth it....especially if you have a smart Tv anyway for netflix etc.