This is great, although I'll probably stick with Travis & Appveyor for my open source project since Gitlab.com currently only has Linux runners.

All three currently have two big flaws IMO though:

1. They all use YAML which is an awful, unintuitive format.

2. The only way to test a configuration is to commit it and push it. Why is there no way to paste a config file in their website and run that?

Hopefully one day we'll get a CI system that supports Windows, Linux and OSX and has a sane config format, and free minutes for open source projects. A man can dream!