For me the most useful feature is the Digital Signature. I can just sign digitally and send it to anyone i want to without printing a copy. Also i use the PDF pages rearrangements very oftenly. One more positive is i can easily add TEXT to a Pdf which is mostly uneditable.
It is very easy to use plus it is free if you need only for basic usage. You can go for business plan for corporate. I use it frequenly whenver I want to edit PDFs.