The real problem I see with ever using Google's product is that their history with keeping products around hasn't been very good. Now, I'm sure they won't pull the plug on Gmail anytime soon, but I'm not that sure about Drive.
I realize the same can be said of Dropbox as well. But like Gmail is to Google, cloud storage is to Dropbox.
That said Google drive is missing some Dropbox features, but it meets my needs.