Azure Pipelines offers many advantages over AppVeyor, with the biggest one being a maximum of 10 parallel builds for open-source projects, drastically reducing the builds completion time.
A pipeline takes about the same time to build on the two CI infrastructures, however the caching feature is currently only available on AppVeyor, meaning that on Azure Pipelines the compressed environment is downloaded for each build consuming about 10 minutes.
This means that we'll save at least 10 minutes per pipeline compared to AppVeyor once the feature is added to Azure Pipelines: https://github.com/Microsoft/azure-pipelines-tasks/issues/9190