So i looking to buy a quality and reliable uptime monitoring service.

I have been testing PingDom free trial, and all the reports went fine. Also the interface is good looking and as public reports to show to clients.

So in terms of use and fuctions, Pingdom is perfect for me, but i wanted to know if Pingdom is a quality / rock-solid / reliable service? Or its just has a beutiful interface?

Any bad or good experiences with Pingdom?

Note: From many other posts i see that Alertra is a quality and reliable service.
So when comparing to PingDom will Alertra be much more reliable?

Thanks all and fell free to give some advices

Best Regards