I am going to put these on my fathers day list. I prefer these over cotton.
Never too late to change. Great for sports, under the swimming trunks. under my sweats and in the travel bag.

For nylon undies, these are very comfortable (excellent texture of the material) durable, and fit great. If you can find the t-shirt (long or short sleeved) version of this (I think it is called a skivvy top usually in the 'long underwear section') buy it! It's the best I've found. Warm in winter and cool in summer and comfortable in both.

These briefs work. They hold no odor, dry quickly, and work quite well as an impromptu swimsuit. They dry with a towel. Without a very close examination, they look just like a black Speedo.
I surf a lot, and have to do towel changes at the beach which are a real nuisance. With these briefs on, I can quickly pull on my wettie without wrestling with a towel.
The brief does not lose its shape in water. Afterwards, I pull off my wettie and towel dry the brief, pull on my shorts and I am done.
Public showers are no problem either. I just wear the brief in the shower and maintain a level of privacy I desire. Then I just towel them off again and they are dry.
I also have Patagonia's Capilene brief and they are in every way an inferior product. They do not hold their shape when wet, they do not dry quickly or towel dry, they look like a brief, and they do not ride low. And they cost more.
One suggestion: Buy one size smaller than you normally wear and only buy black.