The Cloud IaaS market is constantly on the move so an IaaS Provider’s positioning can change within a short period of time.

According to the Gartner Group, Amazon Web Services (AWS) is still way ahead of all competitors and sits in the sweet spot of Magic Quadrant.

Microsoft has made an entry into Cloud IaaS market with Azure IaaS but its offering lacks some of the automation and networking capability, and as expected is Windows centric. However, I expect the automation of Azure IaaS to improve significantly in the near future based on Microsoft concerted effort for market share.

This article (here) provides a good market definition of Cloud Compute IaaS, the recommended use of Cloud IaaS and a comparison of the main players in the Cloud IaaS space. I recommend reading this article if you are considering a move to the Cloud