I think it really depends on your solution and what you are trying to accomplish. The cloud can offer levels of redundancy, speed and security at a much lower cost than if you needed to build it yourself. The process to scale requires less engineering and resources. The ability to link to globally distributed networks and a multitude of technologies with the "flip" of a switch will never be replaced by hardware. I think it takes a combination of the two to architect rock solid infrastructure. Just choose your providers wisely!