Issue tracking system experience..

For issue tracker , I have some suggestion.

Below are those I had played before. My last job is to maintain JIRA for our department about 2 years. 

There are more options like Trac..etc. And github and Bitbucket also has their own issue tracker( why just use that? Click the link for details)

By the way, may I know the SCM system we will use?

Basecamp: Popular and fancy. Also costly.

FreedCamp : Free hosting, Basecamp-like UI (Todo list)

JIRA Agile  : Agile issue tracker. Could be fully customized and easy integrate with CI servers. In could and stand alone versions are available. Free for open source project( are we?) $10 for 10 users (stand alone). Integrate with github / bitbucket easily

Your Track : Agile issue tracker. Easy integrated with CI servers(TeamCity. both JetBrain product like Android Studio)  Integrate with github / bitbucket easily

Mantis : 100% free and customized. But need a dedicate server to host it.

Before we choose an issue tracking system, the requirement should be defined first.

1. Do we want to use in cloud version or host our own system?

2. Do we wan to integrate with CI/ build server? Or we just use it to communicate and monitor schedule/

3. Budget....