Point taken bearkat, It would be good if it was more sensitive as well, but they will never be able to make it as sensitive as the minelabs and I think there's no point of competing in that field. You will be better off getting a second hand GP which by now, say an Extreeme, would fetch about the same price as an Infinium, it's more sensitive and will go deeper because of the coil options. This is for prospecting. Even an SD 2100 is more sensitive with a small coil.
I believe that a larger coil may be able to compete with minelabs with large coils, that would be interesting.
Aurum seeker, if you can't afford a 4500, get an SD, they say that they go deeper on larger targets than GP's and are much cheeper. I believe there might be merrit to this since I have owned a 2000 myself. - IF Garrett don't come out with a large coil.
Coming from the large nugget state, I can imagine it to be frustrating that you can't use a large coil. My patience would have run out. I myself use the Infinium for water detecting but would love a big coil so I can have a reason to use it for detecting.
Don't get me wrong, you can take it to areas in WA and find good gold, but you'l be much better off even with an SD 2200.