I have one a like it a lot. I had one with the bigger coiI, but now use the smaller 8 inch coil and for me, it's easier to pin point, more sensitive to the smaller gold jewelry, more stable than the 11 inch open coil and easier to swing. With the pulse delay you can tune the unit to any condition. Has a nice, smooth threshold and great audio.
Saying that, if you want deep, get one with the open 11 inch coil. Just have a good, WIDE scoop as you will be digging deep and wide holes with the 11 inch coil. And you will find DEEP targets with it. I had a harder time pin pointing with the open 11 inch coil, but I may get one at some point..I have the unit where you can switch out coils.
I have used several PI's and other than my Goldquest SS V2, I like the HH PI the best. I did use my friends Dual Field a few times and that is a nice PI too. For me, the HH PI is better due to it being so light. I have the coil mounted on an Anderson straight shaft and it's the lightest unit I have. Can swing 6-8 hours no problem.
One thing about the HH PI. It is a high powered machine and eats up batteries. If you get one, use Energizers. The copper tops do not work as well on these machines.
JC