The fact that it's so user-friendly, with just one button to track down your website status from different locations around the world! I do not have any dislikes about pingometer as of now but if there are new features being developed for this tool then please let me know.
It would be great if you guys can start thinking along those lines because otherwise i won't recommend you anything other than using it since its really helpful in monitoring my sites' availability across multiple location servers all over the globe. You can compare server load and make better decisions for deploying web applications. Also, its easy to use and has some amazing UI options which makes it very attractive among customers like us who wants to monitor our live applications.