I don't run either of these machines but will say I have just found the happy spot in my machine for gold rings, and it is staying there. I usually have a good idea Im about to dig a ring. Not 100% but I will get a solid number, usually high in the foil range. I don't disc out a whole lot, and have to run the machine on high gain or extremely sensitive. I find rings in local parks, I am usually in a trashy area when I hunt. I run a basic 3 tone and don't change the tone any. Head phones would help if it wasn't so trashy. I believe the pro and gti is equivalent to my machine and both will produce. But things like threshold and being able to change tones to help you hear the targets would be one of things you want to know before buying either one. The chart I am seeing on here is a air test. Depending on where and what you hunt, you just aren't going to need to dig 15" deep holes all day. I would very much like to hear how one performs to the other. No chart, just actual hunts, what machine, and your fav setting(s). Being vlf I would say the machine with the higher freq wins, as it would be more sensitive.