I'm on Virgin 50Mbit also. Speeds
can vary - bear in mind that Metaboli's servers are based in France, so there is a little more infrastructure between 'us' and 'them'. They've had issues in the past with their ISP not talking nicely with UK ISP's (Damn Fro... er... ahem).
Anyway, most of the time the download speed is somewhere between 10 and 30 Mbit. I have noticed that different games will give different download speeds
- this seems to be very random, and mostly irreproducible.
As I've just re-built my machine, I have downloaded a lot of games recently, and I wouldn't say I've any complaints - sure, it could be faster, but what couldn't? There's so little out there that actually can saturate a 50Mbit connection...
I'm hoping, however, that whatever new software they've got up their sleeves (Big announcement deal, etc.) will include a multi-channel downloader, so we can get full speed downloads
Oh - and as to the no throttling - that is a feature of the Virgin Media 50Mbit service. There is no traffic management on the 50Mbit service, whereas there is on the 30, 20, 10 and 2 services. It's another reason for them to charge so much for it
You may wish to try downloading from Steam some-times... that can come down at just 2-4Mbit... or can do 40Mbit.