I'm a Virgin Media cable customer ("50M" XXL, consistently testing in the 20s though) right now, in the process of switching away (BT phoneline and Sky TV first). My exchange is enabled for FTTC (my street's served by two cabinets: one already live on FTTC, the other going live this month), line checker predicts 60/20.
I was a Telewest 512k cable customer, then Nildram in 2005, ADSL24 (still Entanet in those days) 2008, jumped to Vivaciti's new MurphX (ex-Bulldog LLU) after the early WBC/21CN teething problems dragged on, then to back to Virgin cable in 2010 when they offered better speeds than ADSL could.
VM retentions estimated my usage as c 150Gb (which will be mostly off-peak: online backup and scheduled downloads), so I'd want either Vivaciti's Office 15 or 45, or ADSL24's Fibre 30 or 50 Ultra. (Office rather than residential, for the 8pm off-peak start.) A&A are tempting, but would come out a bit too expensive for me I think.
Samknows checker says Downstream Min: 56.5 Mbps Max: 80 Mbps; Upstream Min: 15.7 Mbps Max: 20 Mbps. Exchange is ESPER (Perth, Scotland); routed through Edinburgh 21CN interconnect IIRC, though it could be Glasgow.
Any options I've overlooked? User experiences of either, on FTTC? The native IPv6 with Enta nudges me a little in that direction, and the static IP is appealing on both. Entachoice's historical Entanet load graphs would have been nice, but the two nodes I could be using don't seem saturated any time I've checked recently: has Entanet got over the performance problems since the original switch from the 4 Centrals?