I think so. I've been testing Cobra iRadar, a hardware radar detector that connects via Bluetooth to your iPhone for up to date warnings of police radar, and speed/red light camera detection.
The system consist of a small radar receiver that attaches to your windshield, and a free app that pairs to the receiver and provides mapping, on screen warnings, and the ability to upload either false hits from burglar alarms or door openers, or real locations of cameras that may have just appeared and are not in the Cobra database.
I'm a conservative driver, and don't tend to speed, but I do like the added feeling of security I get with the system running. In my test drives, the iRadar system found some sped cameras I wasn't aware of. At one point, I was surprised it appeared to miss one that I knew about, but when I looked around the cameras had been taken down and likely moved somewhere else. +1 for iRadar.
The app doesn't require the radar receiver, and the radar receiver doesn't require the app. Used alone, the receiver will give you voice warnings of upcoming police radar, but unless it is paired with the app you won't get warnings of traffic speed or red light cameras. You also won't get warnings of new locations submitted by other users.
On the other hand, you can download the app and get updates of police cameras, but you won't get radar warnings. The app is also used to set specific behavior of the radar detector, as there re only power/volume and mute controls on the receiver.
I'm told earlier versions of the iRadar app were a bit flaky, but the latest version available, released this month seemed to be stable. I saw one problem where I clicked a button and the system became unresponsive, but closing the app and re-opening fixed it and I haven't seen the bug reappear.
The app has 2 modes. A map mode, derived from Google, that shows you any known speed or red light cameras, and user reported incidents. ON another screen it shows your actual speed, which is often more accurate than your car speedometer. It also shows you cars voltage, and gives a visual warning of any upcoming activity. The app can run in the background and you will be alerted. You can also use the iPhone at any time without losing any info from the app.
The Cobra iRadar unit is US $129.00 at retailers like Radio Shack and Best Buy. The price at Amazon is quite variable. I've seen it as high as $91.96 but I've seen it down to $84.00 as well.
Remember that radar detectors are illegal in Virginia, Washington D.C. and on military bases. Radar detectors are also illegal in all commercial vehicles over 10,000 pounds.
I think the Cobra iRadar works well, and actually is less expensive than comparably priced units that put all the electronics in the receiver. It's probably not as good as some of the highest priced units, but it worked well and the marriage of the iPhone and the receiver worked very well.