In the 2015 Magic Quadrant for Cloud Infrastructure as a Service, Worldwide, Gartner placed Amazon Web Services in the “Leaders” quadrant and rated AWS as having both the furthest completeness of vision and the highest ability to execute.
In the context of this Magic Quadrant, cloud compute IaaS is defined as a standardized, highly automated offering, where compute resources, complemented by storage and networking capabilities, are owned by a service provider and offered to the customer on demand. The resources are scalable and elastic in near real time, and metered by use. Self-service interfaces are exposed directly to the customer, including a Web-based UI and an API.
Source: http://aws.amazon.com/resources/gartner-2015-mq-learn-more/