Couldn't tell about the phones. I don't use em much.. But it really doesn't
matter what they are from a sound/electrical point of view. A volume
control is sure handy through. That would be the only thing I would want for
sure. If they are packing it with the ace machines, it probably has one..
Or you would think/hope anyway.. You may have noticed the stock speaker
is a tad LOOOOUUUDD!!! Or to me anyway..

Actually, I do use a phone all the time, but I don't actually wear it on my head..
It's just a single mono earphone, and it's clipped to my arm band.
I use it to greatly reduce the volume. For me, it's about perfect.
About the sniper coil.. It's not that it goes deeper, the good thing
about it is it's small and can weed through trashy ground real well.
You'll be glad you have it the first time you have to detect in "busy"
trashy ground. IE: say you are at a park, and there are a few coins in the
ground, but there are also a bunch of pull tabs, foil, bottle caps,etc.
The bigger coils will see more targets at once naturally, and trying to
decide which hits ID as coins can get to be a pain when the ID scale
is jumping back and forth, and the pinpoint mode shows a lot of stuff
close together. The sniper will let you see fewer targets at once, and
you can pick through the trash and get the goodies much easier
than one of the bigger coils.
It's even a fun coil to use on non trashy ground as it's so fast. You don't
cover ground as quick, but sometimes the goodie count will come out
higher per square foot of tected earth.
Of the three Ace coils, the sniper actually has the least depth, but thats
totally natural being it's the smallest.
But it gets 5-6 inches in good ground, which is real good for a 4.5 inch
coil. Coins hit real hot with it, and usually ID about the same as the stock
coil.
Oh yea, in most cases, divide the depth reading in half when using the
sniper coil. IE: if it reads 4 inches, it may actually be closer to 2..
But.. I hardly look at the depth indicator until I get ready to dig..