My first CRK was a small 21 with cocobolo inlays. I followed it almost immediately with a large 21 "pre-Idaho" with bocote inlays. I immediately realized that the small was, well, too small for my hand and it never felt comfortable to me. The large was perfect, both in hand, and in it's condition. It had been someone else's safe queen and became mine. It was just too pretty perfect to use. I bought a KnifeArt large 21 CF and completely fell in love with it. It became a user and my work EDC instantly, and was in my pocket the majority of the time for a year despite buying a crapload of knives over the same period.
I've since sold the small and bought a Wilson Combat StarTac (Umnumzaan), a large 25 Plain Jane, a large 21 Insingo with Micarta inlays, and a Mnandi which is a very occasional dress-up carry in its slip in the bottom of my pocket. Every full-size CRK is a favorite and could easily be my only carry if I had but just one knife. I'm going to have to try an Inkosi and am sure that could be my one-and-only too. I think that one should be natural canvas Micarta--just beautiful.
I have yet to buy a CRK new. They all came off the Exchange. My first large 21 and Mnandi were LNIB. The former is my safe-queen and the latter being a "gentleman's carry" gets no real wear or use. I find it much easier to use an expensive knife if it's already had some before it comes to me. Recently I've had great success buying CRK users--my Micarta Insingo plus a ScotchBrited 'Zaan for my son. The knives are much cheaper and go right in pocket and to work without being babied.
So, if I were to give advice on which one, I'm not much help as any large is great for me. But I would certainly recommend the secondary market for purchase both for price and putting a great knife right to work.
