I've been with Hosting Revolution for about 8 months now, and thought it was about time for a review.
Hosting Revolution offers shared plans ranging from very cheap (and accordingly small) to a plan that's more expensive than Site5's smallest plan (the two are roughly comparable). So while they may look like a dollar host when you see a plan that's $10/year, they're really not.
I've noticed extremely little downtime in those 8 months. Host-Tracker, which I've only had on the site (http://noidzoid.com) for a couple of months, reports about 99.5% uptime. I'm confident the uptime is at least that on average, maybe more.
I've only ever needed customer service once, and it turned out the problem wasn't on their end at all. They literally spent hours on the phone with me helping me to figure it out, which should give you an idea of the service level.
They also have a policy prohibiting porn of any sort (legal or otherwise) and even sites that link to porn. This is something that I look for in a host, because (1) porn sites often hog system resources and cause downtime to every site sharing the server they're on and (2) I'm concerned about being on a shared IP that Google comes to consider a "bad neighborhood" (porn sites often engage in spam).
All in all, this is one host I feel safe in recommending.