I have been using Camscanner for about 7 months now. I use my app in a Moto G phone and the quality is excellent. I recently was in a library with no access to a photocopier, a scanner or the possibility of borrowing the book, and Camscanner saved me.
I scanned over 100 pages, in black and white, with excellent quality, easy to give a title and share through Gmail. Very impressed.
Now, I do not pay for this app, and so have limited storage capability, but by paying a monthly fee of less than USD 5, you can increase to 10GB in the cloud and other 7 features.
Easy to upload to Dropbox, Evernote, OneDrive, send documents through Gmail, etc