TomTom has speed camera alerts built into it, but keeping it up to date incurs a subscription charge.
I also have a Beltronics 990, which is essentially a Euro 550. This picks up all radar and laser emmissions, but isn't infallible. The radar detector element picks up a lot of rogue signals, and the laser bit requires very fast responses from the driver, as it will only alert if a beam is on you, ie, your car is being targetted by a hair dryer laser gun device with a policeman on the other end.
Devices that block/jam laser beams are illegal, as technically you can be seen as perverting the course of justice, but no doubt some devices are harder to detect than others. I understand some alert you to let you know you've been targetted and that the laser beam has been jammed, allowing you to slow down, by which time its deactivated, so when the puzzled officer tries again he gets a reading of your speed, albeit once you have decelerated.
There were moves afoot to ban radar detectors, but I'm fairly sure there wasn't time to put this through parliament, and now the government are too busy nationalising banks and failing to eliminate bovine TB to think about it.
By the way, every thread like this on this forum will invariably feature some people recommending, pointing out and opining...
The Mk I Eyeball.
Never exeeding a speed limit, ever.
Only idiots travel over the speed limit.
Good luck with whatever device(s) you choose!