There is something that has always confused me in discussions on nitro powders, that is worrying which one is cleaner burning. I have never had a malfunction shooting smokeless because the powder was a little dirty burning. Of course I do clean my guns when I'm done or at least within a few days. Unique seem to catch a lot of, "but it's dirty burning." Well a little, but I figured out that by keeping it, I keep from having to stock at least 3 or more powders to do in the guns I load for what Unique will do. Instead of having several 1 pound cans around, I can just buy an 8 of Unique.
What is even funnier, in 3 modern guns I own, ones I'm very serious about performance from, the best loads in them are very dirty, in fact my 7/8th's Oz load in my 28 Gauge that has killed 100's if not thousands of game birds is so dirty a friend tried it in his 1100 and it fouled it up at less than a box, but there is no such problems in my 870. So since it gives me the performance I want and need, I use it even though after a good day in the field the first couple of cleaning patches look almost like I've been shooting black.
Just my thoughts.