I've been reloading for a very long time and used/owned more brands of dies than most of today's reloaders ever heard of. Yes, dies of mixed brands work as well or better than the same.
So far as average results by brand I've learned there is as much variation between individual dies of the same brand as between brands; they are all made to the same SAAMI tolerances. (Occasionally it seems a bad die can get out from any maker but they ALL will replace defects.)
I've found there are two groups that all dies fall into, on average. Clearly, Redding/Forster dies are tied for best because of their full-length body sleeve that holds case and bullet in proper alignment before seating starts. All other dies are tied for second best, and I mean all of them, no matter any cute and costly little gimmicks they may include.
The effective loading difference between the two groups of dies is clear but usually not massive; a really good conventional die set will load ammo just as well as a more costly set. A MUCH bigger issue than the dies is the loader's lack of or possesion of skill and not a lot of "experienced" reloaders have great skill. Neither time at the bench nor volume of reloading means much, of themselves. Some good loaders have ten years of experience, some poor loaders have one year of experience they've repeated twenty (or more) times without learning any more!
Poor cases can easily negate the value potential of any expensive dies. And NO ONE can tell how precisely he has assembled his ammo without using a concentricity gage. Rolling cartridges on a flat plate may expose really poor ammo but no one can tell if the run-out is small and run-out matters.
Micrometer seater heads make it easier for us to set bullets to a specific OAL, they don't do a thing other than that; mic heads can't do anything to improve concentricity or OAL that a conventional seater screw doesn't do.