I don't really have any opinions about the subject, I just shoot straight from the hip. If I don't know by experience, I won't write it to be so, count on it.
Many years ago Garrett and Fisher had the deepest all-metal detectors ever made except for the Nexus. This was back in the 70's. Garrett and White decided to chase the European and eastern US market so they didn't put as much into the makings of their detectors for high iron/salt soils any more. Garrett is more guilty of this than White's. Big mistake! A couple of years ago Garrett tried to remedy the situation by offering an aftermarket chip for bad soils. They didn't quite get it right though, they still suck.
I owned an Ace 250 (past tense) and compared it to the new F-2, and the Ace might as well be left in the truck if you brought another detector costing $150 or more, just like I did with mine. I too listened to the hype and when I got the thing I was really disappointed when I compared it to my cheapest Tesoros, BH's, old Compasses, and several different White's.
If someone is wanting a detector for the first time, the Ace is no better than a low-priced Bounty Hunter, because I own one, a Land Star. I paid 30 bucks for it, the right price. In fact the Land Star may be a bit better. One of the best BH I've owned (in the 70's) found more coins than any other detector I've ever owned, with the Silver Sabre finding the most silver rings and jewelry, and the CZ-70 finding the most gold rings. Out of all the detectors I've owned, all the I've used in the last 34 years and the ones that I've repaired, I can say that Tesoros and Fishers are the least trouble to work on and the least problematic. The A.H Pros were the worst. These new Fishers are the cream of the crop, and the Tesoros are a close second.
Right now, the best (new) all-around detector for the money is probably the Tesoro Lobo Supertraq, but it costs more than many others. It has the best and fastest automatic ground balance on the market, even better than Minelabs, and Minelab's auto GB is really good too. The LST does just about everything right, but doesn't have all the toys. It really is a professional's detector, an excellent cherry-picker, not a toy, and is great in bad ground, beaches, and nugget hunting too, nugget hunting anywhere. It will find BB sized nuggets at 5". The F-4 and F-2 are close, but they are not made for nugget hunting and the LST is.
The best low-priced detector for the money is the F-2, count on it. It is hot! It's light, precise, and keeps up with the high-priced VW's at the dragstrip too.