I've seen many join BE and complain to hell about problems and leave, only to come back again eventually.
A lot went to Virgin, so certainly not anything to do with the BT infrastructure
A particular BEing was convinced all problems laid with BE, moved to TalkTalk (mostly as they said they support Netgears) and within a few months was back again with BE (still complaining from time to time)
In 3 months, I will have been with BE for 5 years. I'm more than happy with the service they've given and that doesn't mean there haven't been problems.
There definitely have been
For unilimited broadband for the price, they cannot be beaten. Vivaciti, Xilo and Sky come close, but have their own issues
In terms of overall service, it's probably A&A that win over all - but broadband with them comes at a price a lot of us probably cannot afford
Be* Unlimited