At 6'4" and 275lbs, I generally wear 3xl long.  I ordered a 4xl long because as any "big" athlete should be aware of in the current climate of cheapness by clothing companies, the larger sizes don't always 'wear' their stated size(see my review of a 3xl Dickies Work Shirt).  One reviewer lamented that his shirt was larger than the stated size.  I pray for that problem every time I buy clothing, especially athletic, nowadays.
Dri-Fit or Dri-Power material is all the rage in todays athletic apparel.  I whole-heartedly support its use.  Far more durable than cotton, the lifetime of this shirt, barring tears, should be excellent.  My only complaint, and the reason for 4 stars versus 5, is the thinness of the material.