Reviewed by new to Vermont from southern Vermont on Tuesday, December 27, 2011
I'm 5'10" and 145 pounds. I purchased a medium (my usual size) after consulting with a STP customer service person. It fit like a glove... the length was fine, but body was too tight to trap body heat efficiently. I exchanged it for a large. Not much different than the medium...just a little longer in body length and a little more body room. Still not enough room for a sweater under it...if you want to do that, buy 2 sizes larger than normal.
Very warm...I wear it all the time and bought a second large which fits just like the first large. I haven't washed it yet so I can't respond to what another reviewer said about that. If this had been 100% merino wool it would have gotten 5 stars.