What is the biggest difference between IBM Rational Team Concert (IBM ALM) and JIRA.

RTC is strong in traceability across the lifecycle, Support for cross-platform development, Cross-project planning , Embedded Source Code Management ( while JIRA requires additional Atlassian product - Bitbucket), Continuous Integration (Build Engine) , easy Integration between SCM and CI, seamless integration with Requirements Management , Quality Management, Design Management, whilst JIRA has very flexible Marketplace with extensions and plugin, Number of available extensions and plugins, simplicity of extending the product functionality (developing plugin or extension), ease of Software as a Service, Recognition by analytics groups (for Agile Planning).

The problem is neither tool was originally built or designed with Agile in mind. Jira was originally a bug tracking tool and RTC was originally designed for waterfall. Thus both have some serious deficiencies when it comes to fully managing Agile projects especially when it comes to enterprise approaches like SAFe or LeSS. My personal preference is VersionOne and more recently Agile Craft has introduced a really good product. I have used what was Rally (now CA Agile Central) and HP ALM in the past. Maybe they have improved in recent years but when I used them they were not as strong as VersionOne. Both VersionOne and Agile Craft have the capability to hook into your DevSecOps environments to help streamline tracking and reporting.

I prefer Agile Central is the most complete and not restricted with about companies that I work, some times Jira is not the correct, JIRA need to design workflow and the expertise to maintenance that will you need when you buy tools whit that features.
When the companies need to resolve some issue in the execution proceed, I prefer a tool who have a quickly deployment and maybe another features to control in the strategy of the companies.

In my experience, I prefer to use VSTS because is a very practical tool for ALM, Jira is more complete for issue management but is more hard to trace subtasks with changesets. If you want to choose beetwen Jira and RTC, I will chose Jira specially for cost and issue management

Our HP ALM tool serves the test management function. Jira is not a test management tool. I don’t really see the comparison. A project that only uses Jira loses a lot in my opinion.

ALM is the test management tool and end users can able check manual their application flows. It was follows waterfall model.

Jira is a defect tracking tool. It is finding the one release has how many defects are closed and how many pending so using for the agile.

I am not an expert on the two products you refer to.
Instead of these, I suggest using CA Agile Central with CA Endeavor.

In short, the fully integrated platform of Microsoft's VSTS (with CI-CD), providing DevOps and hooks to DevSecOps along with the integrated Azure Cloud platform provides the best answer now and looking to the future.

Add Helix ALM to the mix and I’ll get you tons of content!