Yes they are a tad more expensive than other offerings, but so far it seems more than worth it.
I do not use Nimbus, but I use another host that offers "managed" service. I agree that the extra money is well worth the peace of mind! We do not have to worry about updates or security patches to any of the server software (PHP, Ubuntu, Apache, etc.), and they also have a handle on any type of intrusions. If any hardware fails, they replace it--immediately, quickly, and at no cost to us. Customer-installed software (XF, WordPress, anything else) is our own responsibility...but that's to be expected.
Prior to my taking over our big board (which was almost 10 years ago), we were on a cheaper service that our former admin used. Basically, they'd plug the server into the power and the Internet, boot it up, and..."Here you go." When the server and forum got hacked, it was offline for two days while he had to reconfigure everything, reinstall a lot of bits and pieces, and lose a few hours worth of forum content while restoring everything. All told, the forum was not back to normal for at least a week, if not more.
Just shows you that you can never rely on price alone for hosting! I've had a lot of offers to move in the past and, I'll admit, our hosting situation isn't perfect, but I've been there 17 years (joined them in January of 1997) and they've always watched our backs. I had our new dedicated server custom-configured and priced, and it's performing better than I though it would. Hopping hosts for the best price or a
promise of good service is never a good tactic--once you've found one who manages your hardware and software and keeps you running smoothly, it's best to stick with it. Nimbus sounds like a good move!