Not much they can do to improve that, as they're relying on Openreach same as everybody else. But when you phone them up because your copper pair dies every time it gets soggy and they say "Yeah, I can see it in the logs. That's a bit crap. Nothing I can do from this end but I'll get on to Openreach and email you in about ten minutes with an appointment" instead of "Ok, I'm going to talk you through rebooting your BT Hub", it leaves a positive impression.
Oh, and on the subject of stability, they send me an SMS every time my line goes up/down. Even if it happens at 4AM. They don't have to, other ISPs hope you won't notice, it's just a nice feature.
> I don't really understand why support is so important to people.
Support is not important, until you need it.
There are alt-net providers out there (who shall remain nameless) whose engineers are trained to practically breathe down the necks of their customer just after installation in order to get them to post a 5-star review on Trustpilot. However the reality is when the customer has an issue down the line, they discover to their horror that the post-sales support is shit.
Isn't a stable connection more important?