I have one for my Vaq.
The concentric coils will go a bit deeper in low mineralized soil, although the area it covers at depth will be about the size of a quarter.
The DD coils have a much wider scanning field...kid of like a book hanging off the bottom, and handle mineralization better than concentrics.
The disc is good, but not as sharp as the concentrics so bottle caps will act and sound like high tone coins way more than the concentric coils, something that is true with any brand of detector using these coil types.
If you hunt wide open areas I believe there is nothing better.
That wide field lets you cover a lot of ground faster because there will be a bit less overlapping, and it makes me feel like I anm not missing much at all when I use one.
I might be, but I don't feel like I am which is important to me.
Using one of these coils on my Vaq I was running around like a madman looking for just one more good signal in a large wide open field at a park once, and when I say running I mean it.
I was also swinging way too fast but the Tesoro speed and the wide scanning field still alerted me to a target when I got a quick beep so I went back and examined it further and dug a hole.
My disc was set just above foil and there was a tab at the bottom of my 4" hole, but in the sidewall of that hole was also this gold ring.
I am convinced that without the speed of a unit like the Tesoro's or that wide scanning field I never would have found this thing moving the way I was that day.
Paid for the coil and more just with this one 14k find.
thanks folks 
