You might try Exofficio. While I can't speak on their traditional boxers or briefs, their boxer-briefs are great imo. They're comfortable and breathable.

And durable--I've had several for over 6 years and the only thing showing wear is the waistband--buy this is definitely a reflection on me because I got lazy and gained weight.

I originally heard of them from a reddit bifl thread, where I also discovered Darn Tough socks. I vouch for both brands and use them exclusively.