+2 for BeThere (with caveat*). Have used them both at home and work for years:
• No usage limits
• No traffic-shaping
• Low ping
• Configurable connection (speed vs stability) so can be optimised (eg for gaming or VPN)
• Annex M (up to 2.5Mb/s upload speed)
Caveat: BeThere's ADSL2+ speeds can't compete with fibre. BeThere don't do fibre yet.
If your local exchange is FTTC enabled, I'd recommend an FTTC fibre connection. Go to SamKnows and do an exchange search to find out:
BT's version is called Infinity, but it's resold by many other providers (list here):
We've just opted for a Zen Internet fibre connection because we like their pricing model and short contract length. Their usage caps are download-only so you can upload hundreds of gigabytes per month to cloud backups on their cheap but fast 100GB/month plan.
Can't say how FTTC fibre compares with Virgin fibre in actual use, but I gather that Virgin features are much more consumer-oriented, unless you order a Virgin business connection.
Who you choose really depends on what you want the connection for. (I'm more interested in business stuff like VPNs and cloud backup).
cheers, Steve West