The F4 has an all metal setting, the F2 kinda has one too but you have to keep the pinpoint button pressed down all the time to use it.
The F4 has a manual ground balance but only in all metal or pinpoint mode.
It WILL NOT transfer over to disc...no GB on the F2.
The 0 to 99 VDI numbers on the F4 screen are complete and could possibly show up over targets.
I believe the F2 skips a few but this is no big deal at all.
The F4 has a different coil but that can be purchased and will work on the F2 also.
8 vs. 11 visual target ID segments...
I never looked at those things once in 3 years...only the VDI numbers.
For the extra money vs. what you get I never thought the F4 was a great value at normal retail prices.
If you have difficult soil and hunt in all metal all the time it might have some advantages over the F2, but if you hunt in disc most of the time they are essentially the same unit but the F4 just costs more.
I know some hunters that got screaming great and cheap deals on used F4's so that is worth it.
I used the F2 in both horrible and great soils with concentric coils and did well...really well.
Never concentrated on going after really deep stuff, however...I had other detectors for that.
Most of the time I would advise one of the F2 multiple coil packages over the F4 as a better value for normal hunting, or save up a bit more and move up to the F5 which is much more advanced than either one and in a whole different class.
At $400 full retail price there are better values out there than the F4...my opinion only, of course.
Rumors say both will eventually phased out in favor of the F22 and F44 but we will see..