I spoke with NPD and was told the Golden Legion doors fit the best but the wing window fit wasn't perfect. But the heavier gauge doors, forget who makes them had a better fitting wing window but over all fit wasn't as good as the Golden Legion doors. This was for my 66 coupe. I have yet to buy doors or fenders but plan on going with the Golden Legion parts. This is after researching it and hearing directly from NPD.
Finally back in the saddle from the weekend, and I think I need to clear up a bit of confusion (it's easy to get confused on these doors LOL!!)
Our more-expensive heavier-gauge doors with the more-substantial reinforcement bar come from Musclecar GT (MGT), which is the same place that Dynacorn gets them from. Essentially the same doors.
Our less-expensive doors come from Golden Legion (GL).
Good friends of mine who've been in the Mustang Restoration business for decades (they used to do all the install work for Mustang Monthly) had been using the thicker/heavier doors from MGT/Dynacorn, but had to modify them in the vent-window area to get things to fit properly.
Earlier this year I shipped them a pair of our less-expensive GL doors to test-install, and lo-and-behold, THEY PREFERRED them. Said that they had their own little short-list of "tweaks" needed, but that overall they fit better out of the box, and there were no issues to be dealt with in the vent-window areas.
So the above-quoted post had things switched-up a bit. The GL doors are the doors that do not have vent window issues.
Hope this adequately explains/elaborates things for the O.P..
Either way, either manufacturer door will get you to the finish line with a decent fit. It's just a matter of what's more important to you.. 1-gauge thicker metal and a bigger bar inside the door, or better fit and execution right out of the box.