First game you buy is a quid. Apparently you can't sign up without a 10MB connection, but I was unable to verify this.
Tried it on my 20MB ADSL connection and it didn't work at all. The video streamed for 5 seconds and then became full of artefacts that never left and the connection kept dropping. Perhaps it may work for someone with a 50MB cable connection, if anyone's brave enough to give it a go.
I still suspect that the lag will be unbearable for any kind of real-time game, though.
Unless they've changed it since I tried out the American one, you can't use it behind a wireless network either - you need to be physically connected to your router (or, I'm supposing, using Homeplug or something like that).
Otherwise, when I tried it before it was pretty good - and that was without European servers. I'm certain any issues that are going around right now are just load issues you really should expect at launch.
It's a solid project, though the 'console' is technically the better way to be trying it out, so I hope we'll get a few deals here like the US got when it launched the console there - they practically gave it away to existing subs.
I just wish I had the ability to give this a go right now.
Basically, you can load the Onlive software onto your computer, or buy the standalone console. Once registered you can play a lot of big name games (I think the current library is over 100) without the need for a super duper gaming computer, because they do all that for you. Their servers run the game, you play it from that. Effectively, a very complex video streaming service allowing you to play games.
The issues come with the fact that A) latency and lag can be a problem. It won't matter so much in most single player games, 'cos when it's good, it's good, but it'd be more of an issue in fighting and racing games where you need to making split-second decisions. B) Even though, I believe, it streams in full 1080p, it doesn't actually have the clarity of a proper HD visual. This makes it great for small, portable devices like a netbook - which couldn't dream of running games like this either way - but for desktops with big screens it won't really serve as a good replacement for kitting out your own hardware and running the game yourself.
Still, I believe you can sign up, download and play demos for free still, so there's not really any reason to not try it out now that it's officially here in the UK.