I've been hosting with Nexcess for years. Their customer service and reliability are unparalleled. Any time you have a question or concern, they're prompt with their replies via email and phone. Since switching to Nexcess, my site has never gone down, not even once. My email was unavailable a couple times due to the servers getting close to full, but I contacted them and the issue was resolved in mere minutes. I recommend them to all my clients and anyone who asks for a hosting recommendation. I can't say enough positive things about them!