I've ordered several of these shirts, and they feel fairly good on my skin and fit me well.  My wife likes how they look on me, and some coworkers even complimented me on them.

Surprisingly though, after the second time I wore a particular one of these shirts, I noticed a roughly 3 inch tear at the bottom of my left sleeve.  You know how there's that strip that holds the slits that your buttons go into (obviously I am no tailor, as I do not know what to call this part of the sleeve)?  It tore right along the stitch on the inside edge of that.

This is a strange place for a tear to occur, and even stranger is that I didn't do anything out of the ordinary that day that I noticed the tear and had no memory of it tearing.  The material for the shirt feels very soft--something I like about it--but I now have questions about its durability if the sleeve ripped along this stitch so easily and unnoticeably.  I have several more of this type (I dislike shopping, so buy shirts 4 or 5 at a time if I find a type and fit that I like) so I'll be monitoring their durability very closely.