We've been with Pingdom for a while and it's an outstandingly affordable service but their new features seem riddled with bugs (tagging checks as an example), and their API is slow and unusable from Australia (ignores query limit params) - It seems like they're no longer innovating and when I tried to share my concerns there was a bit of a 'who cares' attitude. It's great to see transparencey about this issue, but it could've come the other day when they 'paused' checks for unaffected clients.