I love the cloud and see a majority of benefits in using it and storing data on it. Except safety. And by meaning safety I do not mean only keeping your password safe. I mostly set strong unreadable and not memorable passwords for my accounts. What I mostly fear is reliability.
Let's say that you keep your project spreadsheets in google drive and google decides that you violate their terms. They suddenly close your account and you are unable to access anything. You have an unknown downtime until you find out what went wrong, contact the right people (what kind of support do you get for a free account from google?) and access your files again. And what If they do not recover access to files?
This make me think that everything free is not viable for serious usage. I should keep everything in BOTH the cloud and my computer. This is not portability, this is just a backup system! If I intent to move all my data in podio or trello for example, what do you think is the possibility of failure in the future ?
Another subject of concern is taking your files out of there... In google drive you can't get them directly but export them to word and excel files. Not so practical but at least there is hope (lol).
I would like to hear your opinion on my fears !
EDIT: it might help some people http://www.gtdtimes.com/2010/01/19/how-to-choose-a-gtd-system/