The 11 inch coil is deep but it's hard to pin point. The 8 inch coil I find is a little more stable, pin points a heck of a lot easier and it may be a little more sensitive to smaller targets. I can run the frequency a bit higher too without the threshold becoming unstable.
I hunt with it at the NJ beaches, but I haven't much time to get there lately, hence I was selling my unit. Now that the weather is warmer, hopefully I can get down there and into the water. I mainly use the 11 inch on the wet sand and ankle deep water/suds. The 8 inch is better in the deeper water since you can pin point easier.
If you get one, get a WIDE water scoop. I had a narrower scoop and when I got my wide scoop, it made a big difference. You can get the target with one or two tries.
The unit does tend to use up batteries and works best with alkalines ( not the copper tops). The best thing about the unit is you can tune it to your conditions, easy to use, light as a feather and it does go deep. Also, the unit is set up to find gold and it hits hard on nickels, aluminum, lead sinkers and of course....gold.
Just hope you don't get into a spot where there are DEEP sinkers and locker keys. I hit a spot like that and boy did my arms feel it the next day !!
JC