I second the notion that you may have trouble finding any company that only has been praised online and has no bad comments said about them, anywhere.

People complain more often than they voice their appreciation for something. Part of it's human nature, part of it's that hosting is a service. It should just work. When it doesn't work, then (obviously) people speak up.

You may find the opposite when something is one of a kind (think Prius, in its early days) or has developed a "cult-of-brand" around it. (Then you run into the evangelists, which don't exactly provide a balanced perspective...but that's another story.)

Are you looking for an affiliate program with a service that you use, or just an affiliate program that anyone can join - you don't have to be a customer?