So I compared the manufacturer's specs for the Enlightened Equipment Accomplice Elite in the 10 degree rating, size Regular (6'0") and the ZPacks Twin Quilt also in the 10 degree rating, size Long (6'0"). And it turns out that (unless you're a gram weenie), they're pretty identical. Here's what I got:
Both 900 fill power down
Girth
EE: 86"
ZPacks: 84"
Loft
EE: 3"
ZPacks: 2.75"
Fill weight
EE: 24.39oz
ZPacks:22.6oz
Total weight
EE: 33.93oz
ZPacks: 32.4oz
Price
EE: $695
ZPacks: $635
All in all, very close. The EE is just slightly wider and just slightly heavier – but we're talking 2 inches and not even 2 ounces. Both quilts are the same style opening, and both have a mechanism by which you can close the gap between people at the neck (the EE has a draft collar like flap and ZPacks has a snap closure). EE offers the option of water-resistant down fill, while ZPacks does not. EE is pricier for the comparable model to the ZPacks, but also offers an 800 and 850fp model at a significant cost savings (the 800 is 3 oz heavier than the 900). EE also allows for a more customized colorway, while ZPacks only has two options.
Perhaps the most notable differences are the shell materials, and the baffles. EE uses Phantom 10D nylon throughout, with the option to upgrade the bag entirely to 20D nylon, or just the head/foot areas to the burlier nylon. ZPacks uses Pertex Quantum GL nylon or Ventum Ripstop nylon, and cuben fiber for the baffles. I will admit that I don't know enough about the nitty gritty of either of these fabrics to say if there's a noticeable difference in breathability or durability.
The other major difference between these two bags are the baffling systems. EE uses a vertical baffle for the torso of the quilt, with a horizontal baffle at the footbox. ZPacks uses a consistent horizontal baffle throughout.


