I've carried my GB extensively, and while it's great for cutting packing bands, boxes, tape, zip ties, I have also used it for food prep cutting mangoes and other fruit, onions, potatoes, tomatoes, meat, pretty much almost anything. I rinse and clean it well after every use, and it hasn't even developed a noticeable patina. For CPM-M4 being considered a non-stainless, it stays clean pretty well. Of the 3 mentioned, it feels the most solidly built, and after taking it apart to polish the tang and washers, i can also say that it is the most over-engineered of the 3 (or any other spyderco that I've inspected and taken apart for that matter).
However, ergos and grip comfort go to the Paramilitary 2 and the Military.