Had my F70 since November 28 of last year.
Found my first gold ring within my first 10 hours in a very trashy picnic area right next to a piece of garbage.
Multiple signals but maneuvered that standard coil just right and got a solid 32....no flutter.
Second gold ring found at the outskirts of an old park with the 11"DD, unusually heavy EMI, the ring had a large piece of iron one inch to the right several inches deep, the kind that throws of false high tones, and a small piece of iron one inch to the left and shallow.
I guess you could say there was flutter, I don't know of many detectors that wouldn't have jumped a bit considering.
I was in all metal so I got the gold signal and the iron from both sides, but I still saw enough of a solid signal and numbers from that gold to make me dig it.
Third gold target was again the large DD coil, small heart pendant mixed with silver, a solid zinc signal, no flutter.
Fourth gold was a solid nickel signal with the sniper coil...again absolutely no flutter.
Pretty much every gold target locked on as well or better than any other detector on the planet considering all circumstances.
Not sure what he meant by saying the F5 had a more positive audio response, each one of these I positively heard something and saw something that made me dig it and I am positively thrilled that I did.
I have dug coins at the nine inch range easily, a little flutter because it was an Indian Head spill spread out a bit.
I have dug other targets at 10" using the standard coil, up to 15" using the big DD coil, solid audio at least if not some screen info on a few... not sure I have ever heard of an F5 going that deep.
In most situations digging anything at most sites I get such great information in both audio and on the screen that I can make a pretty good guess on what I will be digging as well if not better than anything I have ever used, and it might sound like bragging but I think I am extremely good at that with my other detectors.
That guy in Vegas, did he ever actually use an F70, I just say that because his didn't sound like it worked much like mine does.
If so he should get better at it before giving advice like this...What is said in Vegas should stay in Vegas.
Now it is true that I have never used an F5, and as a jewelry hunter trying to get better at deep coin hunting if I didn't want the scary depth of the F70/F75 top end I know for sure I would have gone for an F5 and the great amount of adjustability might actually give it an advantage in the jewelry area, but in my experience with the F70 considering what was said about how it works in my opinion there is some misinformation being disseminated.
All Fishers are great and will find the goods, can't go wrong with either one if jewelry is what you are after, and forget about that frequency thing.
I found 10 gold targets last year with the F2, pretty easily too and that thing is 5.9kHz.
But that depth comment above all but also in relation with those other opinions...sometimes you need to take these things with a grain of salt.