Discover Books is a legit company. My books arrived quickly and in good condition.

They are a legit business, but they're unethical. If you're not a collector and are just looking for a cheap book to read that'll be discarded afterwards, then DB could very well fill the bill (unless you have a problem and want a return, in which case you might be out of luck, depending on the affiliate). For collectors, DB should be avoided at all costs. They lie and cheat for gain.

I've ordered once and everything went smoothly. I received the book, as advertised and in great condition. From the order date it took 11 days to receive, which is quicker than what was promised. There was an inventory sticker on the back, but it's small and just looks like a bar code.

Legit
I have never had any complaints worth complaint about.
Hey, one book came with a sticker on the cover that I couldn't remove. While that is a complaint it is not the end of the world. I Tweeted to them that stickers would be better on BACK covers, so books could be gifts. It never happened again.