The content is deployed immediately through the Firebase CLI. Once it's uploaded, the content is served immediately. If you have made a mistake, you don't need to re-upload a new version, through the Admin dashboard you can easily rollback to a previous version.
User registration with Kinvey is pretty good and usually works without any problems. It's also very easy to use, you simply pass the username, password, email, etc. to the required method and register a callback that returns whether the registration was a success or a failure. Same thing is d...
Kuzzle has no hosted version. In order to use it, you have to install it to a remote machine. This can be cost-effective but it also adds overhead because you will have to take care of the hosting and backend infrastructure yourself.
Other platforms have more extensive documentation, sample scripts and cookbook, but to be fair they launched a new docs site a year or so back, and it's getting better. But their support is simply awesome.