Most Microsoft businesses which I worked with use it and I find it extremely confusing. The UI is not very intuitive and it takes me on average 5-10 clicks to get to where I want to go. Most things are not documented at all or not very well or documented wrongly because out of date and things often require hours of trial and error before something works the way the team wants it to be. I'm sure once someone has spend too many hours "learning" Azure Dev Ops then it might pay off if it actually all works, but I find it too frustrating to commit my precious time to figure things out which should be dead simple as other CI systems have proven it can be done.

Oh god Azure Devops is terrible. It's improving over time, adding new features.... but letting existing features which actually don't work continue to be broken.

It's slow, the builds don't refresh properly so you have to always f5 if waiting for a build.

Their hosted solution is also impossibly slow, we ended up running it on a Vultr $20/m machine and it's fine for us (we run 3 concurrent hosted agents). Builds are much faster.

We're in the process of migration, first from Jira to Boards. I have some serious concerns but I'm a marginal Jira user and DevOps newbie, so they all seem confusing to me.

The build pipelines & release management stuff is even more confusing but could be quite powerful. I'm pretty opposed to replacing (even ancient) Jenkins et al CI tooling that works though - seems like a lot of work for little net value.

If you're doing greenfield development in the MS ecosystem DevOps should be strongly considered; aside from the cost savings (it's usually bundled with lots of porgrams/memberships) I don't see huge benefit over say the Atlassian solutions.