I'd bought a few things from ThredUp and been reasonably pleased with the quality and price. One thing was excellent, the rest were fine for what I paid.
My first consigning experience, though, was horrible. I sent a huge bag stuffed with clothes, most specifically from the list of "acceptable" brands on the website. Most were nice things that I've worn for work. All were clean, no stains, no holes. I received $1 for consigning a long-sleeved t-shirt I bought in Montreal for about $15, and nothing else for any of the things I sent. I also never received an explanation, additional payout, or information about where my things went.
I didn't expect to get rich off consigning, but I had hoped that my brand name clothes that met all of the service's criteria would result in a bit more return, or at some communication about what happened to all of the things I sent.
I won't bother shopping or consigning there again. You probably shouldn't either unless your expectations are very, very low.