My Resistance is a bit more snug (especially torso) than the Recon. It is also more snug than the Re-Gen though the shoulders on the Re-Gen are almost as snug. I'm 175-180 and have a Large in all. I would not want it bigger since all are a bit roomy in the torso...the Resistance is the leanest. I can layer with all. Anyway, I have a 42 chest and a 34 waist. The Resistance breathes very well and I have been using it on cold rides (no rain here yet). It is really windproof so windy days are much better now.

I'm 5'11" and 176 lbs today but my chest is a bit overbuilt. Shoulders are wide-ish so mediums would not work. If my shoulders were a bit less wide, I'd go mediums. I hope this helps. I heard of the Oro but needed something fast and while the Resistance does not pack down tiny like one of those super light wind shells. it blocks the wind better, seems much more durable, apparently completely waterproof, and I still pack it into my middle jersey pocket.