I've been thinking about it. I read fast, and I read a lot. I use the libraries all.of.the.time and totally work the system. But I still end up having to wait for a long time to get books I want to read... like sometimes the waiting list is 300+ people with 4 copies of the book or something crazy like that. Those are rare, but almost every book I want to read has a waiting list. And it is weird to have no control over the list, so there have been occasions where I'll get multiple books at the same time and then have a crazy mess. LOL. And sometimes the local libraries don't have the books at all. Although I just found out that we have a reciprocal agreement with King County and Seattle, so I'm excited about that. I need to get over and pick up my cards. Also, my daughter has Prime and never reads her one book a month, so I might borrow it from her. LOL. I think I am going to wait a bit before jumping in to paying monthly, but it does seem tempting.
I am not sure about the time limit, but I believe that you can only have out 10 books at one time. When you try to take out #11, it asks you to put one back. (I think that's what I read; I have been following a thread on another forum, but not closely. The consensus over there seems to be that libraries and Scribd/Oyster have the big publishers and better selections.)
Same. Oyster and Kindle Unlimited don't really have books I'm looking for at all. I have a decent selection from our library, and I am going to get a library card from our nearest big city for a small fee and get books there as well. The library works very well for me. I'm there all the time for my kids anyway so I alternate between reading "real" books and checking out e-books.
I was thinking about it too, because we home-school and it would be some much easier to get the books this way (no English libraries here in Thailand) But when I looked through their books none of our school books were on there, and these are classic and modern literature, not text books. I heard that several key publishers have not agree to let amazon use their books (yet). If they do agree then I am all for it!