I've used a few hosting companies over the years but I have to say the Relentless is the best in terms of customer service. Unlike many other companies, with Relentless you get instant customer service whenever you want it.
So far, every single question I have asked them was answered immediately. I can't write about down times of their servers because I haven't experience any.
So far, these guys are excellent and they are very cheap, with no hidden charges or any other BS.