minelab ex 2 or SE or maybe even an Extera 70

[Chef Geoff]

I know what you mean Paul, I remember swapping from the WOT coil to the SEF on the sovereign and couldn't believe how stable it was, But, the Sensitivity meter on the Explorer range is in fact only telling you how much power is being sent to the coil and not what the coil is doing with it. The simple fact of having a sensitive coil is I'm afraid going to make it sensitive to any and all bits of dross that it passes over (that's the trade off). So I'm not convinced that the pro is any different to the 10X12 SEF.
The upgrade to the SEF from the old slimline coil was the right decision, the slimline apart from it's obvious manufacturing problems was an awful coil and most would shine in comparison.