I don't know if they're the best at everything. I've been using Google Compute Engine extensively lately and I think it is a lot more polished feeling at times than EC2.
Note: GCE live migration take place only when there is a "scheduled maintenance", it is not designed for immediate hardware failure, so it is not a silver bullet and should not rely on them for your service's availability.
You should be building your AWS infrastructure around failure scenarios, and while you should be notified of a failure, your app should continue to chug along.