A little more info may help, but here’s my first stab. Cerium has different models with weights and fill type I believe, in addition to hooded vs non hooded. First lite also has different weights and insulation types.
Are you looking for light weight and occasional use during bow season, lots of use moving during rifle, just glassing bow/rifle, etc? I think if you dial in your intended use and whether you expect to layer with it you’ll get some good feedback.
I have the hooded cerium LT and use it occasionally. At camp during bow season if it’s cold and more layering if it’s really cold and I’m still hunting. Down side I find with it is it’s a bit snug to fit more than a layer it or two under it (or I’m not as thin as I once was...) and mine is navy blue - they now have a better tan color.
I like my FL Uncompahgre. I was camped at 7000’ with the wind ripping up the mountain and was fine. Temp was low 40s and dipping into the 30s. I had a Sika Mountain Jacket to cut the wind. Packs down nicely as well. I have the SG 5900, and based on that alone, I wouldn’t hesitate to get any of their apparel. Id really like a set of their mountain pants.
Really really like my Cerium LT Hoody, I have it in Caribou Brown which is great for hunting. I had a Stone Glacier Grumman and feel it was probably a tad warmer. If I hadn't found the Cerium LT on clearance around $200 I'd still have the SG. I've also had a Uncompahgre but I don't think it is an apples to apples comparison, to me the SG and the Arc'Teryx were much warmer than the Uncompahgre. The Uncompahgre IMO would be a good piece if you needed synthetic down for an early season hunt.
After owning multiple items from First Lite and Arcteryx, I would choose Arcteryx hands down. Arcteryx quality is by far superior to First Lite. I've had mutiple show up new and be defective, or fall apart very shortly after. I've never had that issue with Arcteryx.