Moving from a pad to an underquilt and have been all set to go with the warbonnet 3 season Yeti.
Then, after looking through Hammock Forums, took a look at the 20* Phoenix by Hammock Gear. I'm intrigued mostly because it's just a bit longer (52" vs 46").
Great reviews on each.
Not really looking for recommendations as much as I am just noodling on the matter.
Still, all opinions welcome and appreciated.

I was in the same boat as you. BUT, I already owned 40* UQ, so I then decided to go more for a winter set up. I went with the 20* Incubator. I am very happy with the HG product. I cannot say anything about the Yeti since I have not actually seen one. I have read only good stuff about them.
The draft collar is a very nice feature and makes for a nice, cozy sleep!
Tough choice...but either way I expect you'll be toasty!

I have not tried that one but also have read good things about it. You won't be disappointed in the 20 deg quilt. I had more insulation sewn into mine when it was made so I now have a 20 deg quilt. I have needed it a few nights. I would get the longer one 52".

Yeh - I looked at the incubator today too. Part of me thinks - well why wouldn't you just get the full length set up and not worry about it, you stupid prat?
But I tend to sleep hot - and doubt that I'll do a true winter camping thing - so the incubator may be way more than I really need.

But I like the Phoenix because it's just a bit longer. I'm 6ft and 178 so the extra length may be good.
The draft collars do look grand - but Phoenix is cinchable and can be adjusted tighter on one side and looser on the other for the asymmetrical lay of the WBBB. There were a couple of good videos by Shug and Water Monkey comparing the two, which actually didn't help my decision at all. LOL

No idea about the yeti, but I do have the 20 deg Incubator and I love it. Decided to go this way for my spring and fall camping. I also sewed on Dutch’s quilt hooks because the Incubator now comes with small d rings to clip it on.

These along with the built in shock cord makes for a very fast setup. After the first time of getting it all dialed in it is now just a matter of clip and go. Don’t have to worry about it sliding. If I get to warm it’s just a matter of opening up the ends with the shock cord.

Haven't got the Yeti, but I've got two Jacks 'R Better quilts. I think one is rated at 40 degrees and the other 20 degrees. I've used them both down to zero.

JRB makes good stuff. It's worth a look.