What bothers me about Google’s AppEngine

Its a PaaS rather than a IaaS, so its naturally somewhat opinionated, but its not like Google doesn't have a wide-open IaaS offering. Its more "use the stack we provide for you in our PaaS or build your own stack on our IaaS" than "use our stack or use another provider".

That’s compounded by the fact that the majority of applications on Google’s AppEngine are going to find themselves being forced to also use Google’s BigTable implementation. Well, that’s a pretty huge investment on the developers’ part, because BigTable isn’t really a standard that’s easily deployable on other cloud providers.

Developers don't use BigTable directly, they use the Datastore API. There are third-party open-source implementations of the AppEngine Datastore API that use backing stores other than Google BigTable, which can deployed on the IaaS of your choice.

If anything, AppEngine is more accurately compared to Amazon Elastic Beanstalk, not lower-level services like Amazon EC2 or Amazon OpsWorks.

Yes, AppEngine is a comparatively high-level, PaaS cloud offering. Google's IaaS equivalent to EC2 is Google Compute Engine.

This article basically seems to be complaining that App Engine is bad because it doesn't have the wide open flexibility of an IaaS offering like EC2, which is an odd complaint, because AppEngine is a PaaS, and Google offers an IaaS if that's what you are looking for.

App Engine is definitely more limiting just not as limiting as you think. And, what you fail to mention is what you get in return for these limitations. You get a system that scales with no configuration or maintenance necessary. Even Elastic Beanstalk needs to be configured and maintained because it is more open.

App Engine is really a web developers dream platform. It is just a matter of whether your app will work with its limitations.