Bear in mind that 'quality', 'reliable', 'own infrastructure', 'support' does not equal "cheap" but that doesn't mean you need to pay Rackspace costs either.
With that in mind, there are plenty out there. Darren put it quite well. I haven't followed the Webperf ratings for many years, as they're so susceptible to practices like he mentions - has no real-world relevance whatsoever, much like many of the 'benchmarks' around
I suggest you give a few people a call to discuss your requirements. Looking for downtime isn't the way you want to go about it - speak to someone and get assured about how they run their business and if they have any single points of failure. Decent ones either won't, or minimise it to the point where it may as well be 'none'