I've gone down the route that I can't send out mailers to anyone on a mailing list unless I can expressly prove that they have opted in to receive marketing emails. If you can already prove that you're good to go!
Really depends on what your current infrastructure is to see what would make the most sense for you backup wise. Also comes down to how much you want to spend lol.
Do you mind giving a quick overview of your existing environment?
How many virtual servers are you running and what is the condition of the hosts that you have? How important is it to you as well to have no Single Point of Failure?