I've been using Nexcess to host two e-commerce websites that were built using Magento. For both websites, I've been amazed at the responsiveness and quality of support that I've been getting at all hours of the day and night. To be honest, at the outset I didn't know what to expect from Nexcess but I've been really impressed. I've used other hosting providers for other websites and I can easily say that Nexcess support and quality is better as far as I've experienced it. I'll definitely be recommending Nexcess to several of my friends who are building e-commerce sites of their own! And there are a lot of friends thinking about it because after all, I live in Silicon Valley!