I personally haven't pushed my ZDP to its limits, but the stories I read agree with the perception that it is not that stainless. It does have more chromium, but it has little else in the way of carbide formers so most of the chromium is locked up with carbon and not available to protect the steel. S110V, on the other hand, is a smorgasbord of carbide forming elements. Way more molybdenum, gobs more vanadium, and a helping of niobium that ZDP doesn't include at all. This stuff forms carbides instead of the chromium, leaving it free to inhibit corrosion.
I have subjected my S110V to salty ham juice for two or three days straight at my old job, and it simply needed a cleaning at the end of each day. No rust whatsoever. It's VERY good, whereas my ZDP has a delicate subtle patina forming despite my taking great care to wash and dry it thoroughly after using it on food. In my experience, I agree with the perception that ZDP is semi stainless while S110V is very stainless.
"Be the person your dog thinks you are."