IP in general is a very difficult idea to support. In theory, it’s supposed to reward innovation, but in practice it results in stagnation and price gouging.

Yep, that’s the biggest downside. I look here first, and if nothing, go elsewhere. What it does have is excellent though.

Not exactly piracy, but if the book in question is public domain, my favorite site is Standard eBooks! Very high quality books, with proper formatting and translations.