I have several Queen D2 slipjoints, and have used 2 of them pretty extensively. Overall, I'm very pleased with the D2. One of my users is a whittler, and in my experience it holds an edge longer than Schrade 1095 or Case CV.
I don't find it difficult to sharpen either, but then I reprofiled the edges to about 20 degrees inclusive, and maintain a microbevel that's simple to touch up on a Sharpmaker.
I recall a thread a while back in which someone expressed the opinion that Queen doesn't heat treat their D2 to optimum hardness (i.e. they run it softer). Even if it's true, it has worked well for me.