I've got one and love it. Depth? Up to my shoulder on Iron deep. A little heavy on the nose and in that regards does not compare well to the Hotshot. DD's are great in trash and PP well. I like the coverage I get with A DD, always have. Was around a guy that had an 18" monster after market and he was craving his EXcelerator. I am content with the 14"DD's performance. It is well made and can take a workout without falling apart. Immunity to mineralization is just another plus.
For relics of iron or steel of size or length try a differental magnetometer.I can target my well casing at 20' (feet) horizontal at ground level. If you are looking for iron of size, nothing beats a mag! The bigger, the better. Lousy on chains, so use a VLF or pulse.
The 14'dd has one drawback: The pretty sticker comes off. Sometimes I curse the depth I find myself at and I use a hotfoot for a hand probe along with different modes. Hotfoot is a powerful little bugger: nickles at 5". To be honest, I cannot speak on the stock coil too much as these two coils are my fav's., well I did do some air tests and 14" beats out the stock for the same settings. Ask Gene who has one sitting in the corner if he will sell his- worth a try!
I still want to get a Hotshot myself someday.