I use Dropbox for all SP drawings. The cloud is too sketchy for us. But, we also rarely work on the same project and will check with each other before opening a project we both potentially might work on. I've found with experimenting with the SP Cloud that if two people are working on a project at the same time, the drawings will get duplicated and it becomes a huge mess.
I've also heard of larger companies keeping all libraries, title blocks, common files on a server, so everyone is on the same system essentially. That may be more advantageous if wanting to keep total consistency. You might be able to do the same using Dropbox or another cloud service. I am not too worried about a little divergence from having the exact same everything for us, so we have not done that. But all projects are very accessible from anywhere via Dropbox. I could even come to your house, load SP and go to my Dropbox account and grab drawings to work on. I don't have to worry about sharing with every key as it is not dependent on a specific key.
I sometimes wonder if I put everything on Dropbox (whole program and libraries) if it would work on any computer that can handle it as long as I have my key? That might be nice!