Tony,
As far as depth goes it all depends on what else is in the ground. I find in some of the trashy area my 5 inch coil will go deeper than the stock coil on my Explorer the same as the 8 inch coinsearch goes deeper than the 10 inch BBS on my Sovereigns too. The reason is it is seeing to much trash and nulling out a good signal, this is why we use these small coils for seperation.
The 17 differnt freq BBS is in the disc mode and not used in the all metal mode and this is why the new GT has a auto trak or lock ground balance in all metal and it is disabled in the disc mode.
The Musky is a great detector and it is sensitivie too, but I feel for coinhunting the Sovereign will out perform it and get the deeper coins and leave the trash, now for relic hunting I feel they will be about the same from what i have used the Advantage.
With the Sovereign including the new GT and the Elite a null in disc will be anything that is disc out plus most all iron as they hate iron, so we run little or no disc and go by the tones. Now with these nulls you will have to go slower to get a coin next to iron. With the Advantage I found you could go faster as it dont have to anlize each target as much, but would get more nails or cover up a good coin signal more than the Sovereign would. I wouldnt call it slow to reset,but check each target out more and give you the info so you decide if you want to dig or not.
Like I say the Advantage is a great detector and for the money it may be the best, but from my use the Sovereign can pick out the good from the bad better and get more depth too, but you have to go slower so it can check each and every target out. Like the Explorer it has a learning curve, but not as steep and now with the all metal "Accu-Trak" of the GT it will work better for those that like to hunt in all metal in mineralized ground and can even be used for prospecting.
Rick