Adobe acrobat reader is very good for pdf . I am using this from 2 years . It works very good because the concept is awesome about pdf. The layout and designs are very good . There is three columns local , document cloud and drop box. For having document cloud you have to sign in than you can backup pdf from document cloud. In dropbox you have also add account for having service. I am comfortable for pdf in adobe acrobat reader. Because it does not take time to load and you can easily find your documents in compared to others . Hence it is very useful for us . So use this app as pdf and enjoy the service