As stated by others, this is a very crowded space. To be honest, I'm pretty happy with the free monitoring services I get from Monitis and Pingdom. Your prima

As stated by others, this is a very crowded space. To be honest, I'm pretty happy with the free monitoring services I get from Monitis and Pingdom. Your primary value differentiator (header/response codes against a regex) are more overhead that I have to create when I sign up. For me, just knowing if the system pings and responds on port 80 and 443 is sufficient. Also especially agree with patio11 about the credit system. I'd only bring that in if certain customers are costing you too much to SMS.