The only thing that's stopping me from completely switching over from Dropbox (I use Google Drive a bit too, but mainly for Docs) is the lack of a Sync client. They're beta testing it at the moment, but its still a little buggy and time limited. Apart from that though, it's a fantastic service. The web app is speedy, download times are great, and with the encryption I'm a lot more comfortable storing private docs than I would be on Dropbox.

The Android app does photo backup too, which is one of the main things I currently use Dropbox for.