They're subject to the same bullshit as other ISPs, but you can mostly opt-out.
Openreach based FTTC/FTTP doesn't suffer this problem as FTTC is point to point with no cotention, and FTTP technically could but with GPON you're sharing the bandwidth with maybe 32 other people, not hundreds/thousands in your area, so it's far less likely to get hit.
Have been a cable customer (originally branded as United Artists, then Telewest, now Virgin Media) since the mid-1990s.
Had cable broadband since 2001 (then branded as Blueyonder).
Been through a lot of speed increases over the years: 0.5, 1, 2, 4, 10, 20, 30, 50, 100, 150, 200, 350, 500, 1000 megabits.
Probably had three faults in that time period that needed a call out to fix.
Unless you can get FTTP, no other ISP can compete with them on speed.
I'm in the same boat as you. NTL, Telewest and Virgin Media. I've never had any serious issues of any kind that weren't of my own making!