ProsSiteUptime is inexpensive and has reliable service.
ConsThey don't have minute by minute checks.
Bottom LineIf you're looking for minute interval checks on multiple site this is not the best uptime monitor for you.
I have used SiteUptime for almost a year and they have been very reliable and accurate. The interface could be a bit easier to navigate around in but it allows you to accomplish most tasks.
Admittedly I am only using the free account so I can not comment on many of the advanced features. For a free monitoring service for one domain it is a good deal. If you are looking to monitor multiple domains and have a few more feature at a better price you may be better off looking somewhere else. With that being said if you do go with SiteUpTime you will not be disappointed in there service and that is really the most important aspect of an online monitoring company.
Use SiteUpTime to get a fully featured monitoring service for $5.00 a month. They have a free plan which allows you to monitor only 1 domain.
They provide all of the standard tools that the other monitoring companies provide and some really nice ones when you get to the top level account packages. SiteUpTime currently has over 70,000 websites monitored and is based out of Sacramento California.
Free Plan which monitors one site for you at 30 and 60 minute intervals and most of the nicer features are cut out.
Advanced Plan which is currently $10/month which monitors 6 sites at 5 or 15 minute intervals all of the features of the premium plans plus some really cool stuff. Such as Blackout Schedules, Custom Ports, and a public status page.