I used to be on Sky BB but switched to Virgin earlier this year.
On Sky BB unlimited 20mbs, my PS3 would lose connection a good few times per night, I regularly would get kicked out of multiplayer games, at least 1/3 of my losses on FIFA 12 were down to the PS3 randomly losing the internet connection, regularly suffered from poor download speeds, usually on average between 5-8mbs via wireless.
Since switching to Virgin 30mbs deal, our experience has been much better, my PS3 no longer randomly loses connection and my download speeds have greatly improved, usually on average 10-15mbs again via wireless. I'm able to download 2.5GB demos & games on my 360 within 25 mins with Virgin.
Most Wanted of 2014: InFAMOUS Second Son, Mario Kart 8, Evolve, Destiny, The Order 1886
+ Titanfall, Watch_Dogs, Bayonetta 2, Smash Bros, Murusaki Baby, Hotline Miami 2, Lords of The Fallen, Hyper Light Drifter, Alien Isolation.