We still use it where I work. The long time employees love it, the newer ones are in awe that something so old/creaky still runs. We've been "investigating" a migration to Outlook/Exchange for 10 years.

My only experience working for a company that ran Lotus Notes was in the mid-90s. The company ran on Lotus Notes. All the back office processes done today mostly through internal or SaaS apps was done then using Lotus Notes apps. Expense reports, benefit selection, procurement requests, travel requests, etc were all done using Lotus Notes apps. This is a time when 90%+ of companies still did all this using paper, fax machines and interoffice mail. As a field employee this made my life much easier than my peers at other companies.

Knowledge bases, installation files, patches, etc for all the products we supported were also maintained in Notes databases. Once a day I would sync the latest updates down to my laptop. I then had a searchable knowledge base and all the files I needed for my work without having to be connected. Back then being connected when mobile was the exception and not the rule.

Lotus Notes was a god send for me in that job.

I .. am pleased I no longer have to do that.

Little anecdote.

At my dad's old company, where he'd been for almost 25 years, they still used Lotus Notes. About a year ago, he moved to a new company that uses Office, and he hates it (old dog, new tricks, etc.). His old company is still the only company I've ever personally had experience with that still uses Lotus Notes.

Is it that bad?

Notes is itself pretty remarkable, but suffers from a peculiar UI + dysfunctional efforts from two sides in development (people who wish it was a RDBMS not a document database, and people who don't really have any business writing application code). The complaints about it being kind of an ugly email client are not really of the essence. In addition, IBM has pretty much left it to rot on the vine since the early 2000s. I think "R5" was the last release of any real significance, and even that was not revolutionary.

Here's how bad it is: In the mail editor you are lucky if you can undo one change. Multiple undo is out of the question.