We use StatusPage.io at Spreedly. They're a YC startup and seem to be gaining traction with enterprises.
There are a lot of people using Cachet in the same way as we do and even for services or business that are making money.
If the two are on par feature-wise, I suppose it comes down to the cost savings of maintaining your own versus the time savings of outsourcing the problem to someone else. It might be nice just to forget about monitoring maintenance.