Combine on-site and online...
We're about to move to a hybrid backup/DR service comprising an onsite backup appliance (that can also act as a DR system for one or more failed servers), plus online backup, with the option of running complete VMs remotely via VPN in the event of a complete site disaster.
I wouldn't want to have backup completely online because of the speed and convenience when restores are required. But the online part creates essential extra DR protection. This seems to be the best of both worlds.
(Strictly our online backup isn't "cloud" as we know exactly which data centre it'll be in, but the principle's the same.)