We have used Azure for a few cases and while the ideas and possibilities were intriguing, our experiences have been less than thrilling So far we've had much better success using the Amazon platform.
For example, we tried using just the simple file storage to post some files. You have to have special tools installed to upload something as simple as a file. After getting the necessary Visual Studio tools in place, we found that any file larger than 100 MB required a different tool (which costs hundreds of $$) that could handle breaking up the file into smaller chunks. Bottom line is that we wasted a day just trying to figure out how to upload files. On Amazon's platform, we nailed it in 10 minutes with no special tools.
I know there are other ways to use the service, but it just wasn't a good experience for us overall.