Both have their place, but most of us prefer slim. On a scale of 1-10, 1 being painted-on tight and 10 being diaper-ass baggy, I'd say the ideal range for most of us is about 3-7.
This may already be obvious to many, but I prefer baggy. I find baggy jeans more comfortable, more relaxed, more in tune with my 'denim philosophy', more likely to be respected(I've childhood trauma of being taunted for tapered pants), and less threatening to my already tottering manhood.
Definitely baggy jeans are more "democratic" in that more people can look good in them. They also have the advantage of pairing well with both fitted and looser tops. The skinny jean-loose top combination is tricky and tends to make the wearer look like a chicken (fat body supported by skinny legs). Mainly because of that added versatility, my go-to jeans are baggy. Of course, quite a few people here wear only fitted clothes all the time, so that would explain why slim is more popular.
I like the term "relaxed. That's a pretty democratic term. All my favorite jeans are what I'd call relaxed. Far from slim, but not baggy (ie RB1, Rogan Originals).