I won't go near Google Drive until they fix some serious longstanding issues with the desktop client. The two that caused me to abandon Google Drive (I even have a free TB for 3 years from my Chromebook Pixel): 1. No way to re-sync existing folders on your computer (seriously). I was pushing hundreds of GBs of photos to my Google Drive, and after syncing everything, upgraded to a new computer (the files were stored o…
Dropbox is the best overall; has the best web interface and desktop client. Google Drive is second, but because more of my clients are familiar with, and already have, Google accounts, and I pay for Google Apps already, I use Google Drive.