In My Mac Book Air I never used Adobe Reader because preview does many jobs easier. Some of them I listed below I can directly add my Signature into a PDF or any scribbling directly on a PDF I can drag and drop pages from one file to another file. Copy Paste can work between Macs and iDevices. (Copy in Mac and Paste in your iPhone) I can open any file from my Mail Account and add or scribble right away and send it or forward it directly without a need of any other software. In case if you want to rotate a page you can just use two fingers in your track pad and rotate the page gets rotated. you can duplicate a file just from the file menu and rename it to anything you want Preview works not only for PDF it works for any files.. that a Mac can understand. And there are lot other options as well. The above said options are not present in Adobe Reader (So I don't use it).