I've had lots of great service in the past from OcUK, really really good, though my last contact with them wasn't great, but they were within their rights.
I had a mouse that was faulty under warranty, got RMA number, sent it back recorded with proof of postage, but Royal Mail screwed up and it got returned to me about 3 months later. I asked OcUK if I could still get it replaced, though within that time the warranty had run out and their RMA numbers expire after just 28 days, so I was told it wasn't possible. Would have been nice if they could have accommodated it still but the problem lies with Royal Mail really, who, as far as I know, don't give compensation if you get the item back undamaged? The manufacturer of the product was interested in my experience with OcUK, but after a few emails I've heard nothing more from them, and they don't seem interested in sending me a replacement. The company is Razer.
I've since tried to fix it myself (with no warranty left I figured may as well try!) and it was better for a while, but then the same (double clicking) problem came back. Now it sits next to my desk - the best mouse I ever had and I can't use it. I do have a replacement mouse now, Gigabyte M6980, which is really very good for the money, but it's not on a par with the smoothness and precision of the Razer Deathadder.
Otherwise, really very happy with OcUK's service. I see a lot of bad comments about them over the internet still though. Not sure why. They tend to be people's accounts of bad service and that they're a terrible company, but not really based on much substance, with the exception of some older reviews (which I understand are from where the company was going through a period of growth and no doubt had to hire some less than average staff). No really bad recent reviews, just people's opinions seemingly. Maybe they were banned from the forums?