This is a cool idea, but the Medium size didn't fit me very well. It fit fine in the arm and leg lengths but it had this kind of baggy pouch at the waist in the front that looked weird. This is the first item I have ever bought from L.L. Bean that hasn't fit well.
If you are not planning activity like X-Country skiing this is the best made and warmest long underwear I have found. The material is thick, warm, absorbent, and long lasting. There is no elastic band to wear out and pants droop like two piece long underwear. The fit is oversized and roomy. Very comfortable. This brand is better than Duo-fold's wool blend union suit. I wear both, not at the same time, mind you.