Not to defend
Shopbop, but isn't that A&O's inconsistency?
When I got two differently-sized pairs of 7FAM jeans from Shopbop, I contacted 7 For All Mankind. (They were INSANELY rude about it, but that's a different issue.) Turns out the jeans were actually supposed to be an inch longer than the longest pair I received. It was their quality control, not Shopbop.
To go back to topic, I still return a ton of stuff to Shopbop and they are great about it. Admittedly I buy a ton of stuff, too, but between SB and NAP I am loyal to these two retailers BECAUSE they have free shipping and easy returns. I have noticed that SB's shipping/packing is more careless (I got a giant packing tape roller!) and their phone reps are more snarky, so we shall see what happens as they get bigger.