I find that they accept a lot of old clothes. Which means many options are not currently in style. Also the quality can be suspect. Especially for popular brands like j crew or similar "upper end" mass market. I probably keep about 50% of what I order so there are some good finds. Wish shipping was always free. I also wish they provided much more detailed descriptions of the clothes. And the pictures aren't that great. Clothes need to be steamed beforehand and I can never tell the difference between black and navy in the photos. It would be good to specifically say the color. I would love to be able to search by pant inseam for example. Also they never list dress length which is not helpful when looking for work clothes.
As far as selling, I get most of my stuff accepted and never expect much money so I'm never that disappointed.