I'd like to add that my radar detector has paid for itself by now. I generally drive 3-5 mph over the speed limit on highways, but sometimes will increase that 9-10mph over if I want to do something like clear out of the left lane to let others pass, etc. So, it's not uncommon for me to be doing 70 in a 60 or 80 in a 70, etc. I even have an example of that on one of my videos I was recording and posted on recently. I also tend to pass cars that are doing the speed limit or slightly below because I hate following cars and having a chance of getting roadstones flung at the car.
The radar detector is also awesome at detecting grocery stores.
It's a long video, and pardon for the rattling. I just go the GoPro, and am working out kinks in the mount. The radar detector goes off early for a grocery store, and about midway through the video later on.