As long as everything's encrypted on the client-side (and the client's source code is available for public audit), I don't see any immediate concerns besides the obvious one of "what happens if Torus goes under?".
It looks like there are plans to open-source the server, though, so that problem can be solved if you want to host your own Torus deployment (which I'd likely do for any serious non-personal usage).
It looks like there are plans to open-source the server, though, so that problem can be solved if you want to host your own Torus deployment (which I'd likely do for any serious non-personal usage).