[Christian]

As for time capsule I have heard numerous reports about it being pretty unreliable in terms of product life time and hence data availability. It breaks after a short time, for many people. Plus it is a small device that everybody could easily take away, and with it your data.

Not being an IT security expert I would sync with the companies server. If it uses https then you have a chance that your data stays yours. However, depending on which branch you are in, I would recommend you invest a few bucks into an IT security specialist to set up and maintain a solution that fits your needs. It's an investment but losing customer data can easily cost you a lot more. Plus you can use it as an argument if you present yourself to new customers. Data security is a strong need for many. On the other hand I would refrain from trying to set up a secure solution on my own with the help of advices collected from multiple online forums. Without offending anybody, you never know what kind of advice you will get and if it fails then there's nobody to hold accountable for the loss.