I've been with Vodafone since I moved here over 2 years ago. I've never had a problem, they've always given me what I needed, although I agree my initial contact costs were about £50 a month, which was ridiculous! a few months before my 18 month contract had run out, I had a call from VF asking me if I wanted to upgrade my phone and take out a new contract. The previous month I'd dropped my phone in the bath and it had stopped working so I went to the store and bought a new one (£30 - works like a charm), so I declined the upgrade. They then informed me that they could then cut my monthly tariff down and I would no longer be on a contract, just pay monthly and can cancel or upgrade whenever I want.
My tariff is now £12.50 per month and I get 300 minutes and 1000 text messages. Good enough for me. =)
I do agree that it can be difficult to get results when there is a fault. With all the redundancies, there just isn't enough support to handle all the faults! But if there's any bad press, they'll treat it as top priority