I had both Business and Home connections from Yorkshire Cable which eventually became (part of Virgin). I paid a significant premium for the business connection. The difference when it went down was that when I called Business support I was promptly put through to someone knowledgeable, within minutes the issue was flagged on the support web page and an automated phone recording. The problem was identified and a technician dispatched to fix it.
The Yorkshire Cable domestic service on the other hand... At one time I was experiencing daytime midweek connectivity speed dropping to a crawl. Support tried to fob me off with "someone else on your street must be overloading the connection". After a bit of a battle I got an engineer to visit. He diagnosed the problem as being in the cable to the cabinet (about 600 metres he said). They replaced that at considerable cost to themselves. Fault persisted. Competent engineer turned up, changed a small barrel connector (attenuator?) on the line, problem fixed but start to finish I was on a flaky service for 3 weeks.
That said, recent experience with Virgin's domestic service seems to have good remote diagnostics and people who know how to use them.
My business relied heavily on good connectivity, without internet I'd have staff sat idle so I was happy to pay a premium. No idea if Virgin maintains the price differential and standards but surely the principle of "pay more get better" is a universal expectation. I expect @Slavo12628611 will be really angry that his BMW 1 series car isn't the identical spec as the 8 series at 3 times the price, "it's just not fair that someone paying more gets something better is it?" (Exception: Veblen goods like certain fruity consumer IT devices).
In contrast, dealing with another well known british telecommunications provider for services to the "household name" multinational I used to work for was a total nightmare. The smallest change request would require 4 weeks lead time. When there was a tech problem commonly it wouldn't get logged. It would get fixed and then a call back to say "no fault found", such a common experience that one had to infer that someone needed to massage their service availability stats.