I've been using Haskell for most of my personal projects for a while and, over the last year or so, I've been using it at work. The overall experience is incredible. It's hard to isolate exactly why it's so great, and there are certainly some concrete annoyances (tooling and compile times, mostly), but the end result is still unquestionably the best programming experience I've had with any system.
It did take more effort up-front than other languages I'd used. There's still a lot of incidental complexity with bad error messages and tooling that's hard to setup and understand—although it's definitely improved over the last few years. And it did take significant effort to learn, largely because it's so different from every other language I know. But once I got over the initial hump it's been smooth sailing, and I'm always happy to spend some up-front O(1) effort for a long-term reward!
The codebase at work—written by a small team with different backgrounds and levels of software engineering experience, sometimes under tight deadlines—is still largely a pleasure to read and refactor. I consistently leave code in a better state than I found it, not because I am particularly disciplined but because it is so easy.
I also tend to work on my personal projects on a very on-and-off basis—more off than on, most of the time. I've found my Haskell projects to be much easier to pick up months or even years later as compared to my projects in other languages (largely JavaScript as well as Java, Python, elisp and who knows what else).