I have a server in their cloud, which they've kindly provided at no charge, as a sandbox for me to play in. I've done more than play there. It's been a workhorse, tying together a small community of developers and users that I'm working with. It's absolutely trouble-free, which is why you don't hear a whole lot about it. That's a mistake.
I totally don't mind being influenced by service providers who give me access to their services at no charge. I will always tell you when I have been influenced in this way, but it's kind of a pain to have to pay for everything I review. It gets expensive!
Another thing I like about Rackspace is that they humor me when I have a strong opinion about products they should offer. I realize they're a big company and it's hard to get mobilized around a single idea, the way I, as an individual, can. But one of these days we will make a great product together, because our philosophies are a good match.