cloud systems
Keep in mind that most of the cloud systems are vulnerable in terms of security. Nearly every big cloud host has attracted negative attention lately.
Your multiEngine@easyGoing tool is the safest way to secure your data and have them at hand wherever you go and which ever system you use.

your cloud (blockchain technology)
This cloud intranet blockchain service is a very safe, anonymous, and unforgeable one, available in all versions.
more about blockchain and here (for pro and business version only) upgrade

pflogCloud
Your new ownCloud service is very safe and easy to handle.
Server location: EU/NL (for pro and business version only) upgrade

Dropbox
You synchronise by a Dropbox software which has to be downloaded additionally. Server location: USA
Your data is not secure enough on this server.