Here is one reason Nitrous.IO is superior. I could actually run the php file that was created automatically on the box. I cannot do the same on codio.

Another reason is that Nitrous.IO has a desktop client that uses unison to keep files in sync. This means I develop locally using my favourite IDE and I get to preview it instantly on my nitrous.io box, I say instantly but I'm sure there is some latency, but I'm lucky enough to have an internet connection where CTRL-S, ALT-TAB, CTRL-F5 results in my newest code being ready without having to wait.

Sorry but I was hopeful that Codio could live up to it's claim, but the fact I can't even run their default PHP file is pretty sad.