From my own limited experimentation I came to same conclusion as the author. I think that the platform is nice for toy projects because you do get a fair amount of resources for free. However, there are too many limitations for even a serious personal project. This may change once we finally get official pricing.
Not sure if it's more expensive, even if you ignore the free quota. Amazon charges you $0.10 per instance-hour, not cpu-hour like Google (so you only pay while you consume CPU). Also, you should probably compare the storage price not to S3/EBS, but to Simple DB (you still pay for CPU time spent in the datastore, though).
My problem with the pricing is not that Google hasn't indicated what the pricing will be like, but that if you need more resources there is no other option except hope that Google will be nice to you and up your quotas.
