First of all, root access offers independence from the hosting provider in terms of software. While the hosting provider still manages the server’s hardware, a choice of software is on a user. It’s you, not your hosting provider, who decides when it is the right time to upgrade, for example, cPanel or MariaDB. We cannot say that this freedom is absolute, though, compared to the dedicated hosting plan. If a bare-metal server has hosted hypervisor installed, its OS must be compatible with a guest OS. For instance, if a physical machine runs Linux, it’s impossible to install Windows as a guest OS. A native hypervisor is compatible with any OS. Apart from that limitation (and apart from illegal activities, of course), VPS users can install whatever software they want.
Keep firmly in your mind the sort of assets that you require to serve your site(s) when seeking a host. Cost in a VPS is important, but not as key as you might think. VPS resource availability is scalable, so the cost that needs to be looked at is comparable cost from one host to the next. Also – as cPanel revised their pricing model recently, web hosting companies across the board will have to pass those costs on to users sooner or later. You will need to consider the cost of control panel when selecting a VPS plan. Companies like ScalaHosting has developed their own control panel to mitigate this issue – so their users would have little issues with the price hike.
A virtual private server (VPS) is a virtual machine (something like a computer divided into many smaller machines using special software). They are often used by Internet hosting providers. Multiple VPS's run on the same machine, but they are separated as they will only share hardware resources without interfering on software level. A VPS is dedicated to the customer's needs, has the privacy of a separate physical computer, and can run server software. There are many platforms that can run a VPS. Some of them are VMWare and Xen.
A VPS doesn’t just have more RAM, disk space, and a proprietary share of CPU than a shared account. Depending on the provider, some VPS plans offer burstable memory, which is a pool of RAM set aside for extraordinary events. This is the stuff that can help counter the so-called “Digg-effect,” that much-whispered about occurrence that’s the simultaneous hope and fear of everyone who runs a web site. When you have an unexpected high traffic event, burstable memory will call on a pool of reserved, shared memory to satisfy the needs of temporary high traffic. This is not available on shared servers and, while the necessary memory is available on a dedicated server, your site might not get the kind of traffic on a daily basis to justify the expense of a dedicated server. Again, not all VPS plans have burstable memory, so ask your provider if their VPS plans do.