I have used them in the past, they are very stable but the resources they claim to offer are not accurate, you don't actually get the HUGE amount of webspace or Bandwidth they claim to offer as you will discover if your site over-clocks their CPU but you have to be running some outrageous Crons or Scripts for this to happen. I stopped using them as I purchased a vBulletin license and you need .htaccess to run some functions in that software and they don't allow you to use .htaccess files on their server, they claim it's a security risk which of course it isn't but what can you do. They argue that you can Password protect files and folders as if this somehow makes up for the denial of .htaccess usage, not a problem if you don't need/want to use those.
All in all they are a good hosting solution but they are far from perfect, support is okay so long as you don't have any 'difficult' questions, up-time is hard to fault, I only suffered a couple of downtimes and each time is was for a very short period. They claim to have pretty good search engine functionality but this you can achieve yourself with creating a site map for engines to use and of course submitting your sites URL to search engines to crawl.