But the Redmond firm has also notched up some notable customer wins such as Pearson, Ford, NBC News, dunnhumby and Easyjet, to name but a few.
Microsoft Azure vs AWS: AWS pros and cons
As mentioned before, the reasons for picking one vendor over another will differ for each customer. But there are aspects of the competing clouds that will offer benefits in certain circumstances.
The breadth and depth of the AWS offering is seen as a plus for AWS.
Its cloud service has been around since way back in 2006, and it has build out enterprise-friendly services that will appeal to CIOs as well as development staff. Forrester's 'Enterprise Public Cloud Platforms, Q4 2014' report, written by analysts John R. Rymer and James Staten, gives AWS the highest rating from a CIO perspective [the report also offers analysis for devops and coders].
The vendor ranks highest in many fields such as platform configuration options, monitoring and policy features, security, reliability as well as its service offerings. Its partner ecosystem and general product strategy are also second to none, according to Forrester, and its AWS Marketplace has a large number of third party software services.
Another of the benefits of the AWS cloud is its openness and flexibility.
For example, Transport for London - which also relies on Azure in other parts of its operations - has used AWS to meet spikes in demand for its online services such as its Journey Planner tool.
This predominantly means relying on EC2 instances to deploy a mixture of Windows machines, Linux machines and Linux web firewalls, as well as some S3 storage. The government agency also uses other AWS features such as Simple Email Service (SES), Simple Notification Service (SNS) for push notifications, Simple Queue Service (SQS), its Cloud Watch metrics tool and Route 53 Domain Name Server.
While TfL uses Azure in other parts of its business, such as its Oyster card service, it chose AWS as it met the requirements for its online services.
"When we were looking at the cloud providers and the technology stack we decided we were going to go for was actually a mixture of Microsoft and non-Microsoft products," says Dan Mewett, solution architect for Transport for London.
"AWS at the time was one of the only providers that easily allowed that kind of 'pick and choose' to build the solution how you wanted it."
He adds that AWS makes it easier to use open source tools that run on Linux third party tools such as web accelerator Varnish Cache.
"That is the prime difference: that you can have exactly what you want from AWS - you will probably have to invest a little bit to build it - versus you can get the Microsoft stack on Azure very easily but if you want to go around that it is a bit more tricky."
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