When comparing Momentum vs JIRA, the Slant community recommends JIRA for most people. In the question“What are the best project management tools?” JIRA is ranked 8th while Momentum is ranked 14th. The most important reason people chose JIRA is:
It integrates well with a lot of other tools, including other products from the Atlassian suite. Plus there are a ton of plugins, including charting tools, screen capture, etc.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Beautiful design
Momentum has a different, beautiful background image each day. It displays the time, a welcoming message and a reminder in the middle of the page and hides all other functionality out of focus.
Pro Built-in to-do list
Momentum has a simple to-do list that can be accessed from the bottom-right corner of the page.
Pro Reminds of the day's goal
Momentum asks the user what's the focus of the day and then shows that information is each time a new tab is opened.
Pro Provides with weather information
Current temperature and weather conditions are shown in the top-right corner.
Pro Inspirational quote
Momentum shows you a new inspirational quote, once a day.

Pro Lots of integrations and plugins
It integrates well with a lot of other tools, including other products from the Atlassian suite. Plus there are a ton of plugins, including charting tools, screen capture, etc.
Pro Backed by a trustable company
Jira is developed and maintained by Atlassian, which is not an unknown venture, especially for developers. Atlassian has a great number of other products used by million of users worldwide, including BitBucket, HipChat, Confluence and Stash.
Each of these products have hundreds of thousands of users who use them daily and this has allowed Atlassian to garner a lot of goodwill from the dev community.
Pro Very cheap for small teams
Pro Supports version-focused work-flows
JIRA is not a plain long list of tickets, but can be configured to be version-focused, so planning and understanding the progress in a software project becomes clear.
Pro Great reporting tools
Jira offers amazingly powerful reporting tools like activity stream, different graphs of opened and closed issues over time etc...
Cons
Con Some basic features not free
It costs to use features like changing the background manually.
Con Can't be customized
There are no customization options. Existing items can't be turned off.
Con 4K images not available
When accessed from a 4K display, the images will be bad quality.
Con Can't add bookmarks
You can't add bookmarks to it
Con New releases often change the GUI largely
Sometimes the usage becomes worse, e.g. when creating a new ticket, you need to click the notification to keep it on the display.
Con Locks you inside its own ecosystem
If you use Jira you are pretty much locked inside their ecosystem. For example, if you want to add a tool to your project management stack (like a wiki) more often than not you will have to buy one of Atlassian's tools.
Con Client application support
No free client applications; IDE connector development was discontinued. Users are effectively locked into using web interface which requires context-switching.
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