I've always used Dropbox for my cloud sync. It's worked fine and I've not really found any reason to change. However I see I can sync using mSecure Cloud. This seems 'tidier' than using Dropbox and I'm wondering if there are any gotchas or advantages/disadvantages I should consider before investigating further.
There aren't any gotchas or disadvantages to using mSecure Cloud syncing. In fact, since it's our own proprietary sync system, it's the most consistent and easy to use sync feature we have. Also, the one big advantage, if the feature is needed, is that you can only use the cross-account sharing feature if you also sync via mSecure Cloud. Of course, you may not need that feature, so that might not affect your usage of mSecure, but it's still the biggest advantage.
With regards to security, we never rely on any third party cloud system to keep your data secure. The data is encrypted with your account key before it's ever transmitted outside of the app, so it's safe no matter where the data is stored.