I would not trust an Amazon retailer. I have purchased several sweaters from Aran.com and had one experience where a sweater was sent to me as the wrong size: I ordered a small and a medium sweater was sent to me. The original tag had been cut off and a small tag had been put on it. We washed it and shrunk it to avoid having to return it, but generally I would feel more comfortable buying from Aran themselves.

I will also say you could get one on Ebay first to see how you like them, and also maybe avoid the $35 flat-rate shipping fee. There are tons of Aran sweaters on ebay.