Have you every hosted a website on what you thought was a good host site, only to relise that when you viewed it later, the server was down or incredibly slow?
www.realmetrics.com offers its users a means to first examine these hosts, and determine in unbiased terms the uptime, CPU speeds and reliabilty (among a host of other tests), and statistically provides this to you, in order to make an informed decision.
The way Real Metrics differs from other such sites, is that they offer you objective, data driven metrics, and not opinions. The results therefore are that you see the real performance, and not some convulated scenario that benefits the company.
I have used this site a view times when creating new websites for clients, and it is an invaluable tool in determining the best option for them, that caters to their needs and their budget.