I used the F4 and loved it, It's really an F2 that can be ground balanced in all metal mode and has All Metal mode whereas the F2 doesn't. For the cost of a new F4 you could get a used F75, or for another $200 you could get a new one. I upgraded to an F75 six months after I started to swing the F4. It is a great machine and will compete with the XP Deus, CTX 3030 and other flagship detectors from other manufacturers. I'd take the F75 over the ATP and if you are stuck with a $400 budget, I'd look at the bounty Hunter Land Ranger Pro and use your savings for a good pin pointer.