If you're looking for a top-quality managed WordPress hosting solution, I'd definitely recommend using WPEngine.
They are a WordPress-centric web hosting company, that offers extensive service that goes above and beyond just simple web hosting. They ensure your WordPress installation is always up to date and take care of managing the server for you.
Their servers run at an incredible speed, their support is very reliable and their team are really switched on and finely tuned in to how to make WordPress run as smoothly and quickly as possible.
For more info on why I'd recommend WPEngine, check out my hub on the topic here: http://hubpages.com/technology/wpengine-wordpress-...