For us, Azure was a big win for security compliance and data sovereignty. Those factors triggered the switch.
After the switch, we came to realize that Azure is much stronger in support and in the ability to interface with the Azure product teams to help guide the direction of the platform.
I've seen some recent reports that Azure is growing twice as fast as AWS so I wouldn't count them out by any means.
Yes.
> What factors other than some specific affinity to Microsoft makes a company choose Azure over AWS?
Azure has a decent offering even if you don't have any "specific affinity to Microsoft". You can use Azure to develop products that don't use any Microsoft technologies. Although from my own experience, Azure tends to be a bit rough around the edges especially when used with non-Microsoft tools and languages.
See marketing page: https://azure.microsoft.com/en-us/overview/azure-vs-aws/
We have data residency requirements to keep things in Canada. This actually forced us to migrate off AWS, first to IBM, then eventually to Azure.
https://aws.amazon.com/blogs/aws/now-open-aws-canada-central...
I should mention that this was back in September 2014, where IBM was the only one offering anything in Canada (hence the migration).
Once we'd done all the work to decouple from AWS, it was fairly straightforward when Azure came knocking and offered us a ton of compute credits from their startup program. IBM had also rebooted a couple of critical VMs with no prior warning which left us wanting a cloud provider that took its tenants seriously. This was in ~May 2016 and we hadn't heard anything about a Canadian AWS datacentre, which apparently launched in Dec 2016.
We still use SES to this day because we haven't found a good alternative, so it's not like we hate AWS or anything. Just offering a (dated) perspective on why someone might choose Azure.
CosmosDB was the difference for us.
What do you mean by Microsoft-specific stuff? I run a bunch of stuff there. When I started using these things their PaaS offerings were much more mature than the AWS counterpart (since they focused more on IaaS).
More locations, tho' every major cloud is opening more all the time. A much better hybrid story, tho' this may change once (if) AWS get their alliance with VMware working properly. Better layered applications (X-as-a-service) but that might be a matter of taste - AWS is more about giving you building blocks to build your things, Azure has the blocks but is better at giving you integrated "things" out of the box (e.g. IaaS vs PaaS). Per-second billing, generally better budget control.
I've a bit of experience with both Azure and AWS. There's nothing I could build in one that I couldn't build in the other, tho' depending on what that is, it might be more effort in one of them. For my own personal stuff, I use Azure, it's more fun :-)
What factors other than some specific affinity to Microsoft makes a company choose Azure over AWS?