Given that it takes a lot of prints to dial in those settings from nothing, and resin is not cheap, that is a less than optimal situation. My irritation is only about 25% due to not being able to use the resin, and 75% the lack of communication from B9 that its new material would not be compatible with the the B9 Creator. I delayed ordering more resin (and so have delayed work on several projects) in anticipation of this material. I contacted B9 directly to find out when it was being released; at no time did anybody say, "Oh, by the way, we're only making it for the Core series" which would have resulted in ordering more black immediately instead of waiting.
The black has one huge problem- it's black. I use my printer for scale models. I have to remove the print lines and imperfections before molding in silicone. This is really hard to do in a jet black material, which requires painting with a color that makes these things more visible. I had hoped that the grey would eliminate this step. (I had also hoped that it allowed for thinner slicing, and maybe had a little less z-bleed, but those would have been bonuses over the color.) I've also found that the translucency of other colors makes them equally difficult to use in this way.