I also never cared for the "mixed" look either, but that is only personal choice. Lots of mixed TC's look fine, they were just not my style.
Finish somewhat depends on the "norm" where you call and the species... how close you can bring them in for the shot. You can get away with quite a bit with some preds until they start getting close IOW, but not with felines as much as other species usually. So priority, IMO, for predator hunting arms finish should be what reduces or better yet eliminates flash, and what best hides movement, not its eye appeal to its owner. Its a tool first, not a show piece. What causes flash is a given, but what shows movement depends alot on background. I hunted preds and varmints for over 5 decades and did ADC off and on for most of that time, and almost all of it not wearing any camo and never using camo'd firearms or scopes. So flash and movement especially were easily as important to me as having the wind, knowing their useage of the land and having a good set. From long experience I consider lions the most challenging to fool normally. In part because they got the closest to me detected or undetected, except for a few coyotes and fox that actually ran into or over me. Any movement or flash was a deal breaker and far more important than color with lions, and to near that same point with the other species as well.
So it follows matte is better than gloss, and color might depend on what you usually wear and/or the backrounds where you call. IOW, a camo'd firearm will blend better against camo clothing than a black of stainless one will, and most backgrounds. But I had stands in some areas I regularly called with lots of large black lava rock areas where black everything would have been your camo, and others in areas where solid tans would have been as well as whites in the snow besides various camo's in many others. Way more variations than I ever wanted to buy and manage becuase I did just fine without them. Long way around saying I had both blued and stainless TC's and other firearms that I used successfully for lots of predator hunting, but those that had matte finishes were the first choice.
FWIW