I wear a wide variety of different shorts, depending on my mood and what kinda ride I’m going on. I find the biggest advantage of spandex on a mountain bike is that the shorts never snag on my seat as I shift around the bike on technical terrain.
Most of my shorts have a chamois in them. When I wear the ones that don’t, I either wear them over spandex or limit them to short rides. Riding without a chamois for any distance sucks.