There is no "best for dedicated servers". There is only what works for you. Free is good, but what are you giving up? Low cost is good, but what are you giving up? In this case, quite a lot, unless you know how to manage a Linux server on your own.
WHMCS Guru - WHMCS addons, management, support and more. WHMCS Notifications Extended - Add slack, hipchat, SMS, pushover to WHMCS !!
Always looking for Linux, WHMCS, Support Desk work. PM for details
I myself have been with NectarTech/Rackonline. I had 100% uptime with them since I joined them more then a month ago. If you are looking for a decent provider with great uptime and at comparable price range you should give these guys a try.
They support cPanel and their Datacenter is located in San Jose.