As someone who went out and bought a license and used it frequently for figures in grant proposals and other documents, Visio is excruciating. It's not even much of a learning curve, it's just frustrating and feels like you're fighting it.
This is because I was using Visio where the final product needs to look aesthetically perfect, and the workflow would get you to 95%. But we all know how much manual tweaking it takes for that final 5% -- getting none of the text overlapping, making sure arrow dashes don't alias with each other, making sure colors can be distinguished, moving the logical structures around to get the overall shape and flow right, and so on. That stuff is pretty good, and I've only seen worse in other tools. But it's still excruciating.
Personally, it’s unusual in that it’s an acquired product that’s sort of an Office component and it has gotten worse with every release until very recently. Even Outlook, while awful, gets better.
BTW, Visio isn't the only Office component that was acquired, FrontPage was as well (both the client and the server-side extensions), and even venerable PowerPoint, which was Microsoft's very first acquisition back in 1987.
This is because I was using Visio where the final product needs to look aesthetically perfect, and the workflow would get you to 95%. But we all know how much manual tweaking it takes for that final 5% -- getting none of the text overlapping, making sure arrow dashes don't alias with each other, making sure colors can be distinguished, moving the logical structures around to get the overall shape and flow right, and so on. That stuff is pretty good, and I've only seen worse in other tools. But it's still excruciating.