Pull ups have some advantages over regular briefs especially if you’re active and participate in sports. They breath (they’re all cloth backed), they move with your body, they don’t make much noise under your clothes, they are much easier to dress around and so much easier to put on.
I can’t imagine using a thick plastic backed tape up brief to run, take kick boxing class or go to the gym. Depending on which pull up you use, they can be absorbent enough for 5 or 6 hours. I use Northshore Flex Supreme which I have found to have all the advantages above. They are a bit thicker than any of the others I’ve used, but they are the most absorbent. I have been quite comfortable with them under my gym shorts.
Other times only a full sized high absorbency brief will work. In my case that means during most work days, unfortunately, and at night. Also, I’ve discovered, by accident, that any situation which requires long periods of sitting such as a plane ride or road trip, is best suited for a full size brief. The pull ups don’t have the thick wide bottom padding that a brief does so the liquid has nowhere to go from under your butt which can lead to push out through the back of the legs. This happened to me during a plane ride up from Florida last month. Even though the 2 spots on the back of my shorts were small, I was petrified. I was using a different pull up, Tranquility ATN, than what I usually use. I’m not sure if that would have made a difference or not, but I’m not taking a chance and will use a regular brief the next time.
When I feel I need more than a thick brief, I use a booster pad. And I may do that too on my next plane trip.