Anvil Horn 30

Big Agnes makes some very nice 30 degree bags with air mattress and pillow holders at only 2 lbs and $200 USD. That sort of deal was unheard of just a few years ago. I can't give you a model because they change it every year. Mine is called the Anvil Horn or something like that. If you want to get under 2 lbs then plan on forking out $500 and eliminating the zipper.

Those were just examples for the criteria I listed, which may not be your actual criteria. I actually have that sleeping bag and it's fine for a side sleeper. A bit tight, but still very comfortable. I just replaced it with an Enlightened Equipment Enigma 20 degree quilt in wide size. I was able to drop a pound off of my weight doing so. That's an expensive quilt though, especially in 950 fill. You may want a square sleeping bag, or wide quilt if you're an active sleeper. You don't have to buy an inflatable pad, but they sure are comfortable. I spent years on the trail waking up stiff. After buying an inflatable mattress and pillow, I wake up feeling good. You can also get a foam pad like the Nemo Switchback, which is a lot cheaper, but not as comfortable. Your ground mat (whatever style you choose) provides insulation between you and the ground. We lose a lot of heat through the ground without a pad. The insulation value of the ground pad will be rated with something called R value. Foam pads are usually 1-2 R value. The Neo Air I suggested has an R value of 4, which is approaching late fall, early winter levels of protection from the cold.

Check out the REI outlet online. The last bag I got there was from lightweight Big Agnes, and the discount was 40%. Great backpacking bag so far!

Since it's currently at full price, the Magma is about $100 more expensive than either of OP's choices. The big difference is that has 800 fill power down, where the other two are 600 and 650 fill power. My daughter recently replaced a synthetic bag she bought while in college with an REI model, and liked their new sizing system. I think she may have bought the REI Magma. I have and like a Big Agnes 650 down bag I've had for years, but at a 15 degrees F rating, it hasn't gotten a lot of use in recent years. I agree with u/TheBimpo that, unless they are trying to put a full set of gear into a pack of 50 liters or less, OP will do fine with either of their choices.

I have a Big Agnes single I LOVE so I’m jealous of all the folks here with the double. We have a flatlands fleece double bag and the Klymit double pad because they were the easy buttons through our wedding registry. The bag packs large for my taste but the pad is perfect. We sleep on top of each other at home and love snuggling all the same in the wild. Unless your trips are all ultralight backpacking, it’s quite cozy and romantic!

I would go with a quilt, they are great for moving around. Zenbivy is most peoples favorite, I really enjoy my Big Agnes.