I've had a number of experiences with BA (and several other airlines) along the lines of your recent misfortune. And I'm sorry to hear of your troubles. In my case typically planes go technical, or there's bad weather, or a series of events leading to staff running out of hours. It seems to run at 1% to 3% of flights, in my experience.

Of the major airlines BA is actually quite or even very good at the "duty of care" side - hotels, meals, communications and so forth. And so long as they do that to the best of their abilities, and they are putting safety first then I tend to go along with it, and not make a fuss. As T8 puts it, that's life. Other airlines are rarely as good (KLM springs to mind) as BA.

I've always regarded the EU Regs on the issue as a fallback - broadly cancellations are open to compensation, and delays are currently subject to an extended appeal process which may or may not bring long delays into compensation. But that isn't really the point: if there isn't a safe plane you're stuck, and you're looking to BA to look after you and do everything they can to resolve the situation. Does money really help? So I had 3 delays over 12 hours in 2011, all handled well, and I'm happy to leave it at that. No compensation or Avios requested or required. OK so you've lost half a weekend but BA ultimately can only apologise for that.

The two areas where BA is open to criticism are: (a) they are very reluctant to re-route lots of passengers on to other airlines - they prefer to delay and try to re-run the service even if it's very late. I notice that status does matter in that one. (b) total operational collapse - typically bad weather. Then BA stops being helpful at the airport and chucks you on to overloaded call centres. And you're on your own, and often seething! Not that will get you anywhere faster.