It depends. I dig loads of targets down around 6 inches with stock coil in discriminate mode. Plenty below that too depending on what the target is and how it's situated. Stock coil I always figure on around 8 inches max for coin sized targets. With the 12.5 inch imaging coil add around 2 inches, I suppose, so 10 inches in discriminate mode. I rarely hunt in true all metal but if I get an iffy signal I will use an all metal scan to help me to figure out if I want to dig. I started by saying it depends. So many factors to consider. It varies from site to site too. My honest opinion of the 2500 is that it gets decent depth (again, discriminate mode, not all metal) which is more than made up for by imaging. Imaging is where its at as far as I'm concerned. Also it pinpoints on a dime. Pun intended. I have found silver coins and big coppers at over a foot but that is not a common occurrence for me.
I found more and more deep targets as I got better at detecting. Same machine performing better. There's a lesson there.
Hope I answered your question. Are you buying? Thinking about it?
Chris