"if SLAs were insurance policies, vendors would quickly be out of business.
given this, the question remains: how do you achieve confidence in the availability of the services on which your business relies? the answer is to use multiple vendors for the same services. this is already common practice in other areas: internet connection multihoming, multiple CDN vendors, multiple ad networks, etc. the cloud does not change this. if you want high availability, you’re going to have to work for it."
Well put. As Wener Vogels continues to preach, everything fails. Build your infrastructure where SLA's are a bonus, not a requirement.