Warmth of Montbell U.L. Thermawrap to Arc’Teryx Atom LT

I have a U.L. Thermawrap from several years ago… not sure how it's changed recently. My Thermawrap is definitely lighter and believe it or not, seems a bit warmer than the ArcTeryx Atom LT, partially due to the fleece side panels, but it seems more than that. On the other hand, the Atom fits perfectly, moves with me, and looks nicer. Backpacking, the Thermawrap is my go to jacket. Around town, skiing, climbing (if I was still doing it) I would go with the Atom. Of course, from a warmth perspective, the Montbell UL Down Jacket crushes both and is lighter.

–Mark

1. My Atom Lt's hood easily fits over my helmet (for skiing or climbing) but my T-wrap's hood does not.
2. The Atom Lt is partly a fleece garment, and I consider it only part of a system, not a complete system: I always bring (a) a windshirt to go over or under, to block the wind through those side panels when necessary. But nothing else in its class breathes as well as the Atom Lt. OR, (b) a vest of some sort. OR, (c) if cold, a hoodless jacket, like the Nano Puff.