I've tried a few tools for monitoring uptime, but so far this seems to be a bit more impressive. Pulsetic monitors your sites from several locations around the globe. I added a collection of sites and quickly started to get bombarded with notifications telling me my sites were down. I found that a few locations (most notably Bangalore and Sao Paulo) were failing quite often. However as very few of the sites I manage have any traffic from these countries, I've simply disabled these locations. Bulk import of over 100 domains was very quick. Monitors can be paused, which is also quite useful. Definitely good value