This jacket is warm and doesn't feel too bulky when on.  I bought my normal size and it is slightly snug.  If I don't zip it up it looks like it wouldn't zip, but when I zip it up it fits perfectly over a light shirt, but wouldn't fit over a thick sweater.  I only wish it had a hood and that the sleeves were a couple inches longer.  I am very satisfied with this coat though. I would suggest ordering a size up though.