Originally Posted by Sly

There are several "mainstream" companies that specifically target WordPress. Keep in mind that WordPress is always going to depend on the webmaster. What plug-ins you are using, are they kept up-to-date, with themes, etc.

Is this a mainstream or adult site?

I'd recommend a SSD VPS, keep your install (and plug-ins and themes) up to date at all times and remove any plug-ins/themes that you are not using.