There's one knife that seems to be "undecided". 950, The Rift was/is released under both Blue and Black Class'.

I think the Rift was always intended to be a Black Class knife, but, for some reason, Benchmade sent the beginning ones out in blue boxes.

I don't really see the difference between blue and black class, other than black class knives are less "trick" than blues. They're tough knives, usually in nonreflective finishes, that can handle what you have to throw at them. Blue class knives are really essentially the same, but with added "cool factor", like interesting blade treatments and flashier handle options. Maybe I'm wrong, since I'm so new to the hobby, but that's how I saw it.

For a while I had a hard time telling the differences that set the Blue Class and Black Class apart, but now I've roughly come to the same conclusion that you have.

The Black Class tends to have the more "tactical" look to it with all of them being straight black handles, with the exception of the 950 Rift. The 950 Rift could be seen as "urban tactical" with its "urban camo" style handle. Some of the Black Class models use D2 for the blades, but I think a larger number use 154CM and now some use 440C which can be sharpened more easily out in the field, a benefit seen to some military. These are just educated guesses that I've come to and seen others post in the past regarding the differences between the classes.