Definitely EE (if you’re only considering those two). Unless they’ve changed the design the SD quilts don’t have a system for attaching the quilt to a pad. Thats a deal breaker IMO.
I have no complaints about my EE LW 20* revelation after about 20 nights in 20-55* weather under a silex, and in an EE recon bivy. I use one strap. The second seems unnecessary, at least in the bivy, to me.
Whole setup under 5.5lbs, extremely versatile, what's not to like. If I hunted more extreme temperatures, I'd likely switch to a regular down bag. But for 15* to 60*, this works great.