I have friends who want to do a costume group, so I splurged on one of the Anovos Star Trek uniforms. It's really cool and the body of it was true to size, but the sleeves were SO small. I'm not skinny, but I don't think my forearms are abnormally large and I could barely fit them in the sleeve! Fortunately there are huge seam allowances in both seams of the sleeve, so I let them all out and it fits better. It's also a stretchy material, which helps.
Here are some pics on the dress form, and a few of Uhuru in the original. (I bought the blue uniform - science, you know!)