I was really suspicious when I went GPS shopping, because I'd heard so many problems about metal blocking signals and so forth. I put the tracking key through all kinds of tests in my van, hiding it upside down under the seat, inside the dash, stashing it back inside the compartment for the jack, surrounding it with metal and pointing it in all different directions (it recommends you keep it upright, but I found it doesn't make a difference, this thing still works perfectly!). It's only disadvantage is that as a data logger, you have to retrieve it before you get the tracking info to download to your computer. The battery lasted me about two weeks of regular driving, though, so it more than compensated. But yeah, as a first time buyer of a tracking device and thorough tester, I was highly impressed. It shows on an overhead map (adjustable to satellite images with Google Earth!) the exact path the vehicle took, or an animated time-clocked journey, showing where it went, how long it stopped, when it took off again. No matter how deeply I hid it in the car, it never lost my signal once. Shop around a little bit to avoid overcharging companies, and you might want to wrap a piece of black electrical tape on the green battery light on the outside of the case for better hiding. Definitely an excellent buy, I'd recommend it to anyone with covert tracking needs.