The most impressive thing about hyperPing is that it has no additional software to install, which makes its setup simple too! It's very reliable as well since I've used so many other monitoring tools in my career but failed miserably because of their lack of reliability or poor performance. Nothing much at this point. Just try out if you like using open source products only for your uptimes purposes. They are really cheap when compared with paid solutions and also they have good support team who will help you whenever needed. We use them mostly for our servers' availability checks though we do not monitor all server instances from one single tool anymore now instead multiple ones are monitored separately by different providers such as Pingdom etc.