I like everything about this service, it's simple, easy-to-use, fast, reliable, free, no matter where you are in the world! They have excellent customer support that will get back to you right away whenever needed.
There is really nothing else I can say or point out as an issue, if there were any, they would be resolved immediately. This software has helped me monitor my website 24/7 from anywhere around the globe (even though it does not require being logged into their system). It gives me peace of mind knowing that at anytime something bad could happen to my sites but since I am able to see what problems arise when they do happen, I know exactly how to fix them so they don't impact too many people at once.