Wow, me too. I just had to wait a couple of minutes (2014 retina iMac).
I assume MS Visual Studio Online - https://en.wikipedia.org/wiki/Microsoft_Visual_Studio#Visual_Studio_Online
Other parts of the company I work at use Kayako for issue tracking and they are happy. I think it's fairly cheap, too.
I've used Jira professionally for a few years now, and it's okay for development tracking, but not ideal. It works better for bug tracking, but I wouldn't strongly recommend it, as it's quite expensive and the UI is getting pretty old. It doesn't play as nicely with other tools as some other options.
On the other hand, GitHub has always worked perfectly for me, either directly or via Xcode.
I give Slack a +1.