I've used both and IMO its weakness lies in the fact that it depends on the input from other users, sometimes a user will mark/label a place/point in which they either saw a cop or were stopped by one and upload it to the app so other users be aware when passing through that location. The problem with that is, the cop will not remain in the same location and when you pass through that location the app will through an alert and you will slow down, but only to find out there was nothing, so you speed up again and 5 miles down the road BAM!! there he is or you might not even see one at all.
Just get a real radar/laser detector with a jammer (if possible) and you'll be set, hope that helps.
Rob
It's never "DONE", just finished enough to drive :-) - BigTDogg (MA)