My son has been VERY actively trying to persuade me to look into using Oxygen Cloud as an adjunct to Dropbox. Today he sent me this link which is worth taking a moment to read. There’s also a video to watch that explains/describes the model of file-sharing.
From this you can see that the main difference between Dropbox and Oxygen is the encryption which immediately addresses the recent “scares” about Dropbox releasing information to the US government upon request (of course you can still operate your own private encryption on Dropbox files if you want – but that’s a bit of a hastle).
So, Pete has allowed me to be one of his team members and so “family files” will be shared in the cloud using Oxygen. For any small team of five or less, why not use the free trial Oxygen service. If it meets your requirements, consider paying for secure storage in the cloud.