Recs.
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Specs
Pros
Pro Easy to start with
Getting started with Heroku is very easy. It's a very straightforward procedure and a beginner can set up their first app in two minutes. Often it's just a matter of a couple of git commands and it's all set up and running. The official Heroku docmentation also helps a lot.
Pro Add-ons let you easily add features and technologies
Heroku has a vast list of plugins and services that can be added to an instance. These plugins cover things from databases to email systems. This remove the task of having to install services and setting them up manually. Heroku does it all for you.
Pro Lots of learning resources available because of its old age
Heroku is one of the oldest PaaS providers. The fact that it's been around for such a long time means that it had a lot of time to mature over the years. There's also a massive number of articles, guides and tutorials on Heroku out there for beginners and advanced users.
Cons
Con Further deployments are slow
While starting with Heroku is fast and easy, and the first few deployments are actually very fast, larger applications tend to have slower deployments. It takes some time for the dynos to restart and while they are restarting the application is completely offline. Which means that you can lose precious seconds of application time.