I try various Poly mains and am now sticking with OG Sheep crosses for all. I doubt I could tell the difference of switching the different brands mentioned for crosses, or that it would be so slight that I would adjust right away. But I know I'm not the most sensitive, when it comes to modifications.
My advice is to try various Poly mains til you find one you like the best, and just use one type for crosses so you can get a good comparison. Then MAYBE later you could try different syn gut crosses. Or even a real gut for crosses, which is on my list farther down the road.