* Prices may differ from that shown
I bought this Bluray player for my parents for Christmas. My playstation failed, so they lent this to me until I can buy another. I instantly noticed the difference in picture, sound and motion. Even DVDs look better, they upscale beautifully. A dedicated machine does much better than an all in one box (PS3).
I looked at the 380 (£100) 480 (£120) and 580 (£170). Why the difference in prices? 380 is a standard BD/DVD player with the standard online extras available such as BBC iplayer, youtube and lovefilm. There is also an option to buy a wireless device for £55. Same with the 480, the extra you get is the capability to run 3D-BD (with a 3D compatible TV). The 570 (and 580) have all this but they add the bonus of wireless built in! I wanted something wireless as my folks hate wire running all over the house. If you've not got a wireless modem you can still plug it in by ethernet cable.
So the 580 being the sucessor to the 570? I'm not so sure. I can't comment on the playback quality, but the 570 has 1GB space on board, so you can use this as a mini media centre straight away. Put some pics on it and it makes your TV a photoframe.
As you would expect it has HDMI (2.0), component (RGB), scart and optical outputs. If you have a Sony TV, Bravia sync is convenient as well.
I bought this at £125 from amazon. If you can still find them, get one. Its a great machine. Starts up and plays quickly and even my Amstrad dad can use most of the features on this. It runs quietly, its tiny and it looks smart. I've not yet seen its Bravia connectivity features yet.