I've bought four up to now, the first three were perfect, my fourth was far too small at the back, by 2 inches according to the size chart, despite buying the same size and from the same seller so I am in the process of exchanging it.
As for the material, I have had no problems with, and one of them, a replica Columbia shirt, the material was marked up as Coolmax, and its my best shirt out of all my shirts, including ones bought in the UK, the material is that good. Others are marked up Coolmax but are not of the same quality, but mainly polyester, but I find that type of material is good on cool , wet days when they are warmer than coolmax.
One reason I like them is, they are cheap and cheerfull, if I take a fall and rip my shirt to pieces, its not an expensive loss compared to some of my £50+ shirts