Gday
One of the draw backs with using tracking is that if you constantly wave the coil over an iffy target signal then you can possibly track the target out, and just think that you have only heard ground noise, then you may end up walking away from a deep nugget, I prefer to use fixed and ground balance very often, the other upside of running in fixed is that when the ground changes it will alert you, a sudden change in the ground balance will indicate that an area that has had more past activity and higher mineralisation which can mean a higher chance of gold being present, a bit like when you walk in to an area that has a lot of hot rocks as that usually indicates the presence of nuggets as well.
cheers
StayyerAU