I used to work in the trade and sold all the various GPS detectors and this Road Angel GPS Speed Camera Detector is the one I chose personally. Compared to the Snooper equivalent, it works better, is more reliable, has more features and is cheaper to buy and update. It's only been wrong occasionally and these have always been warnings of cameras that are no longer there or of ones on side roads running parallel to me. All the competitors do the last one, so must be unavoidable! The only problem I've got is the sound it insists on making when it powers up. The echo it makes in a multi-storey at 3am is impressive though!!

This Road Angel is the only GPS Speed Camera Detectors I've owned so I can't really compare it to anything else. But it works as it was supposed to, you get plenty of warning for cameras, schools, congestion charge zones and blackspots, plus you can configure the settings to all sorts of levels - LEDs, distance, sounds etc.
It's really helped me slow myself down (9 points already)and I've found myself driving a little better because of it. I used to go a little over the speed limit on cameras to allow for inaccuracy - but not now as the clear MPH readout seems to be spot on. At £400 and a subscription of £49 per year, the initial cost is a little high... but how much is your licence worth to you? Highly recommended - we should all have have one.