You need to consider other factors.

Fit - if the bag is too big you will be cold because you have lots of air to heat and circulate. The fit of the hood is particularly important. Can you get it tight?

Collar - any bag for below 20 degrees F should have a good collar to prevent drafts down your back.

Construction - the bag should be constructed so that the filling stays in place and there are overlaps so you do not have a cold seam.

Zip flap - should be large and well insulated

Foot design - I really like the foot boxes that are allow for feet to stick up without smashing the filling.

Give me two specific brands of bags with all the specifications concerning the above items and then I can make a judgement.