It's like anything in life...
....you get the people with such poor service that they scream and shout bloody murder about it, then you get the people who have good service and never hear from them.
Myself, I'm somewhere in between the 2 groups.
I pay out about £60 a month for the XL TV package, 20MB broadband and just a standard phone line.
TV: The only problem I've ever had with the TV is that the On Demand service has (very) occasionally dropped out, but this has always been down to a fault on the network and resolved fairly quickly. I do get occasional freeze ups when in the EPG, but then I don't use it a huge amount so I'm not too bothered.
Phone: The one sore point about my service with them. During the install the 2 guys they sent out couldn't get the phone service working. They did come out again the next day to try and fix it without any joy, a call was logged with the call centre and someone came out a few days later and had it working in 10 minutes. Since then it's stopped working again, which I've yet to report to be repaired as talking with the customer services team is a painful experience (see below).
Broadband: I've never had any problems whatsoever with the broadband service. It's always been running at full speed (except for the traffic shaping during peak times) and I frequently have no problem downloading at ~2300kbps. Sure the upload sucks, but if you need to have things that fast and bittorrent isn't cutting, there's other services out there to accommodate (read: Usenet).
So do I have any major gripes with VM? Sure, the customer service.
When I've had to call the couple of times that I have, firstly I'm in a queue for ages, then I get through to someone in India who is usual about as helpful as a broken leg. I had an issue with my broadband where it had cut out suddenly so I called up and was told by the lovely Indian call rep after being in a queue for 20 minutes that they were transferring me to someone else. I then got through to a native English-speaking person who told me the issue with my connection is that I owed £105. Surely not I said, as I'd recently paid my bill (which did seem low, a problem I figured was on their end). However what I hadn't been told when I signed up is that broadband is billed for separately and that they'd been e-mailing my bills to an address I apparently setup during the cable modem registration process. Naturally I was a bit miffed by this and forked over the minimum needed to get my connection back up and was told I had to pay the rest the following week to avoid another outage. Ok, fine.
Move along to the following week when I called up hoping to use the automated service to quickly pay my bill, only to be greeted by an extremely slow talking automated system that couldn't understand that my Maestro/Switch card doesn't have a start date. Cue another phone call to India. This time I got through to someone almost immediately which threw me for a second and I explained exactly what needed to be paid. I give over my card details, nice this will be over in 2 minutes right? Wrong. The person I was having to deal with first of all couldn't find both of my accounts (why TV/Phone and broadband are on separate accounts I don't know) and then when asking for the card number he took it down incorrectly, despite me telling him so numerous times after he kept trying unsuccessfully to put through the payment. After about 20 minutes of banging my head against my desk he got it right. I then asked for paper bills for both accounts so I can just deal with things myself.
Sorry for the long post, but in summary, I've had no real problems with the service provided, but the customer service leaves a lot to be desired. Those of you screaming that people should move to Sky should remember that at the end of the day, they're really not any better and if you're a private tenant like myself, you can't just have a dish slapped onto the side of the building.