I ordered a Tall/Medium for my husband, which is consistently his regular size at LL Bean and this should could have fit two of him! It is enormous! I ordered two different colors, and both were like this. Maybe order a size smaller.
My son is tall and thin. He needs the length of the shirt without it being to big around. This shirt is the perfect fit for him. The sleeve length and length of the shirt. He tried it on and asked for more of them so cudo's LLBean.
I have only tried the shirt on as it is a winter shirt, so I cannot speak to the unshrinkable part. The shirt feels like a good quality shirt, and it fits nice. True to size.