Leafs that is a bit of a loaded question. "worth the money" Certainly for some it would be, and for some it wouldn't be, the main reason is the higher up the price ladder you go the fewer the number of units there are.
Also I have not yet had the oportunity to give this latest edition a try for myself, so can't really say much about it.
Since you did also say "your opinion" I'll say this as an older person with less than perfect eyesight, I certainly like the BIGGER id numbers, and screen info. I find the ATPro a bit hard to see, the iron disc numbers are near impossible to see. This alot of people won't like this but, the newer Teknetics, and Fishers are def. faster, and better at being able to find the goods in amonst the thick iron than the Garrett. That is just a fact. And that is why I do like, and use AT Pro, but is not my "go-to" favorite machine.
Whenever these this vs that comes up there is always a lot of debate. So I'm preparred to be bashed, but at the same time I have actually used them both, and in some cases on the same site, and I can think of a couple off the top of my head, if need be I'll elaborate more on those sites, and the results.
Again about "worth it" it has a lot to do with customer satisfaction. I once bought a coat at Mark's WW, for 300.oo I thought it at the time an outrageous amount of money, and I guess it was, but here it is 20 (or so) years later, I still got the coat, and I like it very much, don't mind spending money, as long as I get something good. Unlike a recent TV repair, but that's another story.
EDIT, going back up this thread to where you said your dad looking for more depth. The F75 "should" be giving 2-3 more inches on a coin sized target. They are advertized as 15-16 inches on a coin.
More questions, write me direct, I don't check in here everyday, (sometimes) and I forgot to check messages here for many months, I just noticed I have some. SORRY.