I just received a Yellow CV Stockman and the F&F is great! No issues, no play, very good edges out of the box. The last 3 or 4 Case knives I bought are all the same way, very nice quality.
I own about 10 yellow handle CV knives(my favorite) and none of them have had a single problem. As you have found, they have had no issues. I have 2 amber bone med stockmans in CV that are weaker in the springs. My thoughts are that Case knows the yellow handles are generally users so they make sure they SNAP open and closed. But that is just my opinion.
As far as the CV...all I will buy. The real cutting difference between CV and SS is in the way the blade goes thru whatever I am cutting. Then patina'd CV has less resistance as it cuts thru material, the SS seems to have a little more grab to it when it cuts thru. For example, cutting thru a block of cheese. The entire CV blade will slide thru but the SS will grab as it goes thru. I'm not talking about the cutting edge but the main part of the blade.