I bet the quality if panels from both companies might vary by make and also by batch. I agree, if you pay way more you expect it to be way better. The fact one co. panel is slightly heavier metalmight be because of damage during shipping Years back when I was restoring quite a few cars every year, I would travel 1 hour to Harden's ( since out of business) and pick up my sheetmetal. Yes before Goodmark, and AMD, we would or thru 10-20 qtr panels looking for ONE that was not dinged to heck and back!!
Bout any panels will need some tweeking and trimming. The difference is between some and a whole lot!!!