Met a fellow in the park the other day who was an experienced detectorist and was using a Radio Shack Discovery 3300 and left his top of the line units at home to hunt in this new park...In any case I tried the unit and it really impressed me. Now my question is the F-4 an improved 3300 or a total different unit..Although never used the F-4 would feel for certain conditions just might be a nice midline machine if it was built along the lines of a 3300..appreciate your thoughts...so any input fire away...