Speaking for myself, I down-voted because of the absurd false dichotomy of comparing Google App Engine to $2/month shared PHP hosting! It's like complaining that an oil tanker costs more than a rowboat.
The value proposition of App Engine is that with no systems administration expertise you can rent an extremely reliable, massively scalable web platform that is managed around the clock by a world class devops teams. Unsurprisingly this costs money. If you don't need the reliability or scalability of App Engine, no one is forcing you to pay for it. But it's absurd to suggest that you can get anything remotely comparable in PHP for $2/month.
Thanks for the explanation. The reason for the comparison is two-fold. First, there seems to be a section of GAE users who use it solely to host a blog, a need satisfied by a much cheaper service elsewhere.
Second, while I understand the value of high availability and not having to worry about Ops, I am talking about cost per HTTP request. Here, the $2 PHP host is a clear winner. As I said, that does not mean it is better. Your analogy with the oil tanker and a row boat is applicable: one is more appropriate if you just want to cross the pond. The other is better for going from Alaska to California, with the caveat that GAE exists in the world where there are vanishingly few cost-effective ways to use it.
This comparison is still absurd (and incredibly naive). If you have a few hundred requests per day, sure a PHP server is far more efficient use of your box. For that matter, if you have zero requests per day, it's more efficient to just power it off.
At any kind of scale, PHP's model of "start the interpreter, load the code, start executing" is abysmal. To make efficient use of CPU resources you need compiled code - JIT or otherwise. You often need to make use of instance RAM and pooled database connections. Long-running processes are vastly more efficient when running flat-out.
If you have the interpreter live and the code loaded, you're circumventing the parent's "point" that GAE is inefficient because it keeps your application running in a process vis-a-vis the standard way appservers work in java, python, ruby, node, etc.
But if you need the reliability and scalability that App Engine provides, I still think it's cost effective compared to attempting to build the same functionality yourself. You get the benefit of directly using the work of Google's top flight App Engine programmers (e.g., Guido van Rossum).
By way of comparison, I've done quite a bit of work w/ the AWS components (e.g. EC2, S3, SQS) that in theory allow you to build a highly reliable, highly scalable site but in practice there's still a lot of assembly required, whereas w/ App Engine that's provided out of the box.
I think you misunderstand him. He was using PHP to illustrate the efficiency of request handling and the lack of in AppEng. Whether he got it right or wrong technically doesn't deserve a downvote.
The value proposition of App Engine is that with no systems administration expertise you can rent an extremely reliable, massively scalable web platform that is managed around the clock by a world class devops teams. Unsurprisingly this costs money. If you don't need the reliability or scalability of App Engine, no one is forcing you to pay for it. But it's absurd to suggest that you can get anything remotely comparable in PHP for $2/month.