i'll vote for performance brands. i've worn them a long time, and just picked up the aforementioned $39.95 (on sale) bib shorts.
i think it also depends on your body chemistry. i've RARELY had a saddlesore or other 'situation' and i ride almost 15 hours a week in the summer under all conditions. even the cheaper ones, i find comfortable. the only problem i have is when there is a damn seam in the wrong place. that just drives me to drink.
i have some bellweathers and canari's as well. by and large, i'm good with the cheaper brands though.