Some considerations when comparing TCO of AWS and other models:
Capacity Planning, Utilization hard to predict. Do you buy for peak load?
Need to consider total cost of ownership, not just cost of a single piece of hardware.
Duplicating datacenter in the cloud is not apples to apples comparison.
Need comprehensive analysis across organization.
TCO should be determined over multiple iterations.
Apply cost benefits of automation.
Consider tiered pricing.
TCO includes power, cooling, adminstration, hardware, software maintenance, redundancy.
Time to market - time to get, set up hardware.
Cost of over capacity.
Cost of disappointed or lost customers if not enough capacity.
