I use it daily. I can't study without it. I'm a heavy user and I'm quite satisfied with how reliable it is. It can handle thousands of pages in different tabs. Makes iPad worth it for me I have two and have the app installed in both.
Love how easily I can download any webpage and turn it into a pdf file without leaving the app. I can then highlight text and scribble anywhere. I've tried similar apps. It is the best out there. Thank you for making my life conveniently paperless!