AlertSite is VickeryHill's perferred method of website monitoring. While a bit more expensive than Alertra, Alertsite's worldwide infrastructure provide the level of monitoring needed for websites and online storefronts that have to up and running 24x7.
They offer a whole suite of monitoring products for internet-based applications:

They have monitoring servers running in countries on 6 continents including:
If you have serious need for high-quality monitoring of your web server uptime, performance or even web-based transactional monitoring, AlertSite are the people to call. Let us know if you want us to help you with server monitoring.