dotCloud vs Google App Engine: What are the differences?

What is dotCloud? Deploy, manage and scale any web app. Build your ideal application stack by combining powerful cloud services. Experiment for free, then go live and only pay for what you need. dotCloud enables developers and IT organizations to deploy, manage and scale their applications with unprecedented ease and flexibility by assembling and customizing powerful pre-configured stacks and services.

What is Google App Engine? Build web applications on the same scalable systems that power Google applications. Google has a reputation for highly reliable, high performance infrastructure. With App Engine you can take advantage of the 10 years of knowledge Google has in running massively scalable, performance driven systems. App Engine applications are easy to build, easy to maintain, and easy to scale as your traffic and data storage needs grow.

dotCloud and Google App Engine can be categorized as "Platform as a Service" tools.

Some of the features offered by dotCloud are:

• Develop faster- Don’t waste time with servers. Just select the services you need, combine them in a stack, and get back to writing code. It’s like playing lego!
• Don't worry about ops- We keep your app running 24/7 with built-in load-balancing, monitoring and failover. Scale in seconds to handle surges in traffic - and only pay for what you need.
• Not just for throw-away apps- Create maintainable, future-proof applications with a service-oriented architecture. Build custom services and network topologies. Need custom support, pricing or SLAs? We do that too.

On the other hand, Google App Engine provides the following key features:

• Zero to sixty: Scale your app automatically without worrying about managing machines.
• Supercharged APIs: Supercharge your app with services such as Task Queue, XMPP, and Cloud SQL, all powered by the same infrastructure that powers the Google services you use every day.
• You're in control: Manage your application with a simple, web-based dashboard allowing you to customize your app's performance.