Apart from being pretty slow, I don't think Jira really sucks once a) it is configured to your needs b) you know how to use it (which should be fairly easy with a in place). Which goes for pretty much any tool more complicated than notepad, so to speak: it's not like the other similar tools out there are much better, just different, imo. Though I have the impression a lot of people who think Jira sucks might be using it where they actually don't need it because much simpler tools could suffice in their particular situation.
All tools suck in a way that actual reality of doing work is complicated and tools are obviously way simpler so you end up trying to reduce the reality to fit the model of a particular tool.
That explains why email is still the most used tool. It also sucks but you can do any type of project with email and everyone knows how to use it.
