I have started using Dropbox for cloud storage recently as some of my friends shared content on dropbox with me. Although I'm mainly using Google drive for all such personal storage but for friends content I downloaded this.
There are couple of things which I didn't like and also this software lacks, first, less storage provided upon joining while Google gives 15gb they are providing only 2gb and after that either purchase premium or invite friends which in itself is lots of efforts. Second, you've to download their app no matter what otherwise you won't be able to stream videos shared by friends there is no option of playing on browser. Although the app is smooth and can't comment much on the security but I think Google is still better in every aspect.