I am on Azure as well for my startup (sharpplm.com). We are a document/quality management system for small mfg companies. The app was built as a straight .NET web app with sql server backend, so I went the VM path for now. Since its bootstrapped, Bizspark really has helped cut the startup costs. So far I've been really happy, also all the other software is a nice added bonus.

Yes, we run two webapps on azure, migration was super easy (we were on amazon before) its pretty straight forward couldn't be happier to be honest. We applied to bizspark and got accepted (which was also straight forward). So since we have Azure free for a year we deployed our apps pretty recently actually. TBH, not that any of the services are that complicated, the UI is way better than Amazon's, amazon has a strange way of doing things even on amazon.com. In short, clean, easy to scale, and does the job.

edit forgot this: startup is www.bemvi.com

We're using Azure Web Sites for our site (public/admin), planning on using storage and cloud services soon.

It's been very fast and perfectly reliable, also free thanks to BizSpark =)