Unique dates back to pre world war II, it has been that long lived and reliable. The name unique is used because it fills so many loading needs, from shogun, pistol, small case rifle and with care and know how, reduced loads in large cased rifles.
I have not reloaded any unique in .357 for about 10 years now,the last sitting was to load a large quantity of .357 at one sitting, it took most of the winter to load 300 boxes at 7.5 grains per shot.
I agree with others though, I never knew unique was dirty, I have shot it in every gun I have ever owned, except those that were designed for smoking powder. If you want dirty, try some of this modern day ball stuff.
Old manuals list unique for .357 with charges that scare even me, I have tried it clear up to 8.0 grains and more, 7.5 should be listed as max in everything .357 that isn't a pressure gun.
The one downfall to unique is the sharpness of the muzzle blast, it sounds different that anything else, and will ruin your hearing sooner, even in the field I carry and use earplugs.
I have never used unique in a .45 Colt, but have in .44 Spcl. and Magnums with good results.
Good luck and safe shooting.
Ray