I wasn't introduced to these through Birchbox. I, in fact, ordered these directly with a Black Friday code that brought them down to 1.78 for a pair, fairly risk free.
I have to say, I had my doubts about $16 underwear, but these boxer briefs are worth it. Now, being a man one size too big to order what they have here on Birchbox, I've had my fair trouble with boxers and boxer briefs fitting, keeping elasticity, and the such. I'm a few months in.
I bought more.
I will buy more.
I suggest you do the same.