I have an F70 now and I'm impressed. The build quality is fine for a light detector and it has the kind of lightning fast response that I've heard the F75s have. But, it is different in a bunch of subtle ways than any detector I've used before and I'm hoping somebody is going to write a decent book on the Fisher F-Series of detectors, because the documentation that comes with it is extremely poor and actually assumes you've used a detector before (I have, but that is beside the point). I can say that is has better depth capability than the MXT I've been using for the last two years. I discovered this by using the slow sweep speed option on a known target that the MXT barely picks up on and the F70 clearly picks it up and identifies it as a good target at 11".