It's very easy to use, has great documentation with examples of how it works for different applications, is priced reasonably (it was free when I used), support team are quick at responding as well! Nothing really came out about this software in my opinion but if you're looking for something simple then they may not be able to do what you want them too so make sure before buying into their service.
If anything we were using Nagios which did monitor our services perfectly however there wasn't much else other than some graphs could have been added but no big issues here either way though. Monitoring web servers - specifically PHP/Apache ones without having to install additional tools or agents.