I put stock Shimano Ultegra 6800 Calipers/Pads on my most recent build, and have been very happy with them.

I'm not too picky about pads.

Do some pick up debris (sand/aluminum shavings) worse than others?

One complaint. Some of the Bell pads are slightly wider than my brake tracks on one bike, and tend to tear up the decals & finish on the rims.

After wearing out a brake track once, I was worried about track wear, but I think that was a lot of winter downhill commuting miles on a rim that I had gotten used and damaged before building the wheel.