eh, I'd ignore people who say that low prices make you look less reliable. Being new makes you look less reliable. In the infrastructure market, it's traditional to start at the low end and work your way up, and SysAdmins are some of the cheapest people you could ever meet, so having a fully functional low-end product is a good thing. If you want a reputation, you need to earn it.

That said, SysAdmins are also an inquisitive bunch. As someone else pointed out, you need to document where the test servers are, and what happens when one test server can reach the site but another can not.

If you only have one location doing the checking, or if you can't handle the case of the site being accessible from one place but not another, well... that's a very important feature. Additional servers are cheap; but you will have to do something sensible when one monitoring site says it's up and another says it's down, and that's a moderately difficult interface problem you need to solve (and one that most monitoring software does badly.)