I bought mine through them, it’s very slightly more expensive (less expensive than I’d consider a dealbreaker), but I don’t see anything that’d make it worse than other registrars. At the same time, I’m not very familiar with how other domain registrars work, so I’m probably not the best person to give a review
Last I checked (which was some time ago), pandoc-bin doesn’t require the haskell dependencies. I saved quite some installation time (and screen space during installation) by switching.