I've just moved from a house that was Virgin cable and it was absolutely shocking. The above limits where just terrible, with a house share of 4 adults, only myself a "heavy" user, we would soon hit the throttle limits and then that was that for the evening.
Customers on the "M" package will be throttled from 2Mb/s to 1Mb/s download speed and 128Kb/s upload once they have downloaded 350MB during the eight hour period. "L" subscribers will be allowed to run at full 4Mb/s speed until they hit 750MB, when downloads will be capped at 2Mb/s and uploads at 192Kb/s. Premium "XL" punters, paying £37 per month for 10Mb/s broadband, will be rationed to 3GB at full clip: anything more will come downstream at 5Mb/s and go upstream at 256Kb/s.