I ve never used the F75, but did get some time in on a 1270. very sensitive like the Tejon. Found myself turning the sensitivity way down to avoid alot of small bird shot and bits and pieces, but also dug some rather small good targets at almost unbelievable depths. 1270 and Tejon both have plenty of power to spare! I find my Tejon to be just as deep and sensitive as the 1270 and its easier to run smoothly. I ve read some people have trouble with the Tejon in mineralized soil. Ive been using a dd coil on mine and haven't had any such issues with the moderate to heavy mineralized soil i hunt in. Im sure you cant go wrong with any of the three mentioned.Ive had great luck with the 1270 and the Tejon. Cant comment on the F75, but Fisher makes great machines so id expect it to be good.