Hi,
Unlike Monte I have fairly high hopes for the X-Terra 50 for nugget detecting, with the caveat that when I say that I'm comparing it against other general purpose detectors that might be used for gold nugget detecting. Machines like the White's MXT, Troy X5, Tesoro Vaquero and some others.
If you want a machine PRIMARILY for coins, relics, jewelry, etc. but might use it a time or two to look for gold nuggets, then I believe the X-Terra 50 may be a viable candidate for the job.
The problem is it is too early to tell. Field tests need to be performed in real gold fields. Much will depend of the availability of the higher frequency coils, and how well they handle mineralized ground.
Again, I must reiterate that what I am talking about is how well the X-Terra 50 will do for gold nuggets as compared to other general purpose units, not dedicated gold machines.
If you are even halfway serious about gold nugget detecting, then a dedicated gold nugget machine is the way to go. My main two gold getters are my Minelab GP 3500 and Fisher Gold Bug 2. But I have found a couple pounds of gold nuggets with my White's MXT, proving that a machine designed with general use in mind can find gold in the right places. The MXT is the favored machine at Ganes Creek, Alaska because the huge amount of iron junk in the ground combined with moderate ground mineralization favors machines that have good discrimination capability combined with good sensitivity to gold, with lighter weight detectors preferred.
Kind of sounds like I just described the X-Terra 50!
I also have no doubt there are mineralized areas where the X-Terra 50 would fall on its face for nugget detecting, and only a dedicated machine like the GP 3500 will serve.
As far as your your basic question of Quattro vs X-Terra 50 goes, I'd have the X-Terra 50 myself in a heartbeat. The incredibly slow target recovery of the Quattro put me off. It is also less applicable for prospecting than most detectors.
Steve Herschbach