I just got a couple of knives in from Fowler made out of W2, and I have only played with them a couple of days, but yesterday I was cutting up an apple and just for fun made some really thin slices. After eating the thin slices, I noticed a really bad taste. I don't know how to describe it exactly, but it tasted a little like blood.
At first I thought it was a bad apple, but it seems that the steel was reacting with the food, so I cut up some identical chunks with another knife, tasted them and then took another chunk and rubbed it against the W2 blade. Yep, the W2 chunk had the 'taste' and the other one didn't. I even did the same blade wipe thing with my O-1 Ealy and those chunks tasted fine.
This is really the first blade that I have had a strong food reaction happen with, and I am hoping that once the patina develops, it will fade away, but is W2 known as a very reactive steel?