Confluence

Real-time simultaneous editing
Ease of finding and organizing what I've written
Constantly adding new features
Integration with Jira and Trello is great, but also works as lightweight project management by itself

Honestly, they've fixed my biggest cons, like storage space (now you can buy a bigger plan) and they keep adding more things.
I think my colleagues would say there's still a learning curve, which is understandable, and I think Confluence has been changing the interface with more tips and features for new users (which is sometimes confusing for long-time users like me, LOL)
One big con is still the limited integration with MS Office. Confluence fully replaces the need for Word in most cases, so that's not a big deal, but I wish the Excel integration and/or the table functionality was better.
Also, printing is pretty tough when you have tables.

Confluence is a great option for existing Atlassian users looking to seamless integrate an active knowledge base into their project workflow. With direct connection to the JIRA project management platform, Confluence allows you to connect existing users directly to relevant project documentation. Its base functionality is fairly intuitive for novice users, and its advances permissions schemes allow you to create a variety of admin tiers that can restrict access to relevant users only. The integration between Confluence and JIRA is as simple as checking a box in the user admin panel.

As a general word processor, Confluence can be a little clunky when compared to the UX of similar processors such as Word of Google Docs. While its advanced features can be very useful for more experienced users, available tutorials can be difficult to come by and are often outdated. Like most Atlassian products, the bounty of features, settings, and schemes can be very overwhelming to the average user and are not overtly intuitive. Document organization can also be very confusing, as there are a variety of options to choose from when creating parent and child pages.

The ease to document a wide variety of software related information makes it a strong tool for the teams it has been developed. They also have made it very easy to use several templates for meetings etc. If you integrate it with the main product Jira, then you have a very good combination of tools for software development and follow up documentation.

To work properly with confluence you should also use Jira as project management tool. It is hard to implement it without Jira.To make proper documentation a lot of extra plug-ins make your live a lot easier. Some are free, others are at a cost.Integration with office, google workspace etc is hard.