I purchased size M, which is suggested for ages 10-12 because my son is 10. Right out of the package, they seemed just right for him but definitely too small for average sized 11/12-yr-olds. Now that I've washed them? They'll be snug on him! So make sure you size up by at least one size, maybe even two sizes if your child is more than 50% for height/weight according to growth charts. Size medium, after being washed, would be more appropriate for 8/10-yr-olds in my opinion.

As for the quality? Hanes is a good brand, so the quality is fine. But they really need to change their sizing recommendations for boys' tees.