Both the 3-season and winter Yeti have an asymmetrical cut which has a little more material in the left shoulder area for better coverage where you need it. To my knowledge this is the most unique feature of this UQ.
IMO the ease of installation and adjustment while you are in the hammock can't be beat with the continuous shock cord suspension system. I didn't carry a sit pad before but now I don't know how I lived without it. I'll often use my UQ for an around the campsite quilt to throw over my back or legs while hanging around camp and then just throw it up on my hammock when I turn in. I think this configuration is a great combination of multi-use utility and weight that is only rivaled by the Jacks R Better UQ with the head hole, which is heavier and you don't get dual use from the sit pad.YMMV.
Now once I invest in a TQ, if I went with the JRB no sniveler, I could get the poncho functionality, have the full length UQ option, but primarily use it for TQ. Combined with the Yeti over my legs and sit pad under by butt I think I might be comfortable around camp well below freezing without any additional insulation weight beyond my sleep system.