What are some alternatives?
When comparing UPDOWNtoday and Site Down, you can also consider the following products
WebGazer - Monitor your website's availability with WebGazer, review its performance and get instant notifications when your website goes down. No installation required and free plan available.
IsItDown RightNow - "Is It Down Right Now" monitors the status of your favorite web sites and checks whether they are down or not.
Hyperping - Cheap uptime and performance monitoring with detailed reporting and flexible alerting
Ruler - It's a screen ruler for Windows.
Oh Dear! - Website monitoring, without the hassle
Pingdom - With website monitoring from Pingdom you will be the first to know when your website is down. No installation required. 30-day free trial.