I think Heroku is usable with a similar level of effort -- and you have a much easier migration path to something else if you're not using Google's proprietary datastore IMO.
It's important to understand that that Appengine is not AWS. It is a massively distributed system providing scalability and fault-tolerance that you would need something like ten AWS servers spread over several availability zones to replicate.
Slow - true, request responses can be several times slower than a single AWS server. That latency is due to the distributed nature of the datastore and memcache - but that buys completely seamless scaling. So if you think you need speed to handle lots of requests, you don't. Appengine will spin up as many instances as you need to manage your traffic.
Expensive - I'm a nasty mean bugger so if there was a cheaper option, I'd take it. A single server on AWS might be slightly cheaper, but ten AWS servers spread over several availability zones (and the sysadmin to manage them) are definitely not.
OSS - ummm, you haven't read the article, have you? You have access to the source code of pretty much everything.
Stable - in the early days of the master-slave datastore, we did have occasional outages. But in the last four years we've had a single outage that affected our customers. I thank my lucky stars every time AWS has a hiccup. Furthermore when there is an outage, I know there are better sysadmins than I could ever afford dealing with it.
At the end of the day, it's the usual horses for courses. If you like doing your own sysadmin, Appengine will fill you with horror. But if you are a developer, Appengine abstracts the system admin away so you can concentrate on doing what you do best.
Google seems to be giving a lot of love to GAE recently, especially with Managed VMs. They have delivered substancial improvements to the reliability of the platform.
EDIT: note that the issue I mentioned only affected 1.29% of the apps on GAE according to Google.
You may want to take a look at Managed VMs. All of the new runtimes are based on Docker images, are entirely extensible, and don't require the use of the original App Engine APIs:
https://cloud.google.com/appengine/docs/managed-vms/
You can use whatever Database or NPM modules you want.
I'm currently trying to get my feet wet on GAE. Judging from your statement, are you suggesting that people should look into Managed VMs and maybe skip the regular GAE (or known as the original GAE)?
Perhaps the original GAE will be deprecated in the future?
Disclaimer: I work on Compute Engine, not App Engine but I'm familiar enough with their thinking.
I'm also very excited to see GCP people responding to any GCP questions and/or clarifying its past "reputation" with a calm manner ;). Clearly the tide has changed (probably comes from the top too? :)).
Me and my partner are planning to invest a significant amount of time to the GCP ecosystems!
One suggestion: Make a cloud storage product option free up to a few megabytes for hosting small personal sites. Maybe it exists already but I haven't found it.
There are a ton of options on what you can achieve inside the free tier. But the simplest one for the use case you seem to require is to author a static html site in a good WYSIWYG html editor and then deploying it as a static site in GAE.
Edit: My use case is to move a couple of static sites to a host that supports a secure HTTPS connection by default, which App Engine seems to do: <https://cloud.google.com/appengine/docs/python/console/using.... I'll try moving one of my sites over and set up SSL with with a certificate from <https://letsencrypt.org/>.
2014 App Engine is also different from 2016 App Engine, hopefully a lot of the problems you had have been addressed.
(I work for Google Cloud Platform)
https://github.com/AppScale/appscale
Disclaimer: I work at GCP, so I'm geeked about open approaches to solving problems :)
Last year I moved a personal project (https://www.gitignore.io) over to Heroku and it's been awesome. My whole application runs in memory on a single free dyno. the service uptime has been great and Heroku's pipeline system (Which is basically like Amazon's internal pipeline system) is really good for testing in staging and then going to production.