The most valuable feature is the Scrum board.

The main power of this tool is the integration between the different products of the Atlassian suite. We have good integration with work management and Software build automation (Bamboo).This is the major strength from this provider. 

The most valuable feature is the integration with the other Atlassian products such as Bitbucket, Confluence, and HipChat.

The Atlassian ALM suite consists at least of JIRA, Confluence, BitBucket and HipChat - just the tools you need for organizing your teams in a very efficient way. The most valuable part might be that those tools play very well with each other. 

JIRA lets you work within projects for organizing your work, while Confluence gives you all the tools you need for documentation work. If wanted, you are able to link Confluence pages to JIRA issues and vice versa. This helps a lot if you need to work across teams or sites or even countries.

Using BitBucket, you could organize your code within projects and repositories. It is also possible to refer to a specific JIRA issue within the commit messages, which uses JIRA to link a specific commit to a JIRA issue. Within the JIRA issue, all commits can be seen and direct links to BitBucket show the viewer the related changes within the code. In addition, even pull requests (and the discussions inside) can be linked with a JIRA issue.

If your team needs to discuss certain aspects of the code, you could either use the comment feature within JIRA or create a channel for the issue within HipChat - and just chat. The chat log will be linked to the JIRA issue, which means that any viewer will be able to comprehend why you implemented a specific feature, for example.

Another very valuable aspect is that Atlassian lets you download all products and host them within your own site. This is very important for companies where data control and data safety are part of the company policies.

For a number of internal business processes like hirings, employee transfers, changes of pay, and approval of commercial documents, we run them all through JIRA workflows.

We're starting to push the boundaries of what we can do with Atlassian ALM. It's served us pretty well and we like the flexibility of being able to create custom issues, fields, etc. We've invested in a number of add-ons to give us additional functionalities with JIRA and Confluence, the latter of which is our de facto documentation tool for living documents (stories, reference information, procedures, etc.). We're able to take advantage of the integrations between JIRA and Confluence, for example to show a list of JIRA issues on a Confluence page, and vice versa.

Also, we've invested in Stash, which is our repository for any software development we do. There's not a lot of integration from Stash to JIRA and Confluence that we use. Obviously, we can track bugs and link them back to comments in Stash, but Stash is mostly a standalone solution for us.

We're hosting JIRA, Confluence, and Stash in the cloud with AWS.

With Confluence, the most valuable feature for me is when I tag a ticket in JIRA, Confluence becomes aware of the ticket's status. Bitbucket automatically links them, but I haven't found that to be particularly useful. If I open a pull request, Bitbucket is not good at giving me a link to JIRA, which is something that I would expect it to be smarter about.

In Bitbucket, the reviews are pretty good. It does a good job of picking things up. The review interface is great. It makes super-clear who's making comments, what people are commenting about, and inline comments. The diffs are relatively clear. It does a good job keeping track of which comments are still relevant, and which aren't.

The tasks feature is pretty nice, where you can open a task in a pull request and it'll stop you from merging it until you have completed the task. It's relatively nice and configurable to work with Jenkins and similar tools.

I use JIRA and Bitbucket for the same work. I feel they're really quite separate tools and do different things.