VPS installation on SSD storage is much faster than HDD, where managed platforms offer a pre-installed partition available instantly after sign-up for a new hosting account and some "bare metal" partitions take longer to create. Unmanaged plans usually require the customer to install the operating system and web server stack software on a VPS plan personally. Cloud VPS plans offer snapshot services like Bitnami that can speed up web server installation and CMS application deployment considerably. Beginners will prefer managed VPS plans with CentOS and cPanel for a near identical user experience for multi-domain management as on shared Linux hosting plans.
ScalaHosting allows you to have your own fully managed cloud VPS with a control panel and daily backups.
The force driving server virtualization is similar to that which led to the development of time-sharing and multiprogramming in the past. Although the resources are still shared, as under the time-sharing model, virtualization provides a higher level of security, dependent on the type of virtualization used, as the individual virtual servers are mostly isolated from each other and may run their own full-fledged operating system which can be independently rebooted as a virtual instance.
If you are familiar with hosting control panels, shell commands, and you have basic server administration and troubleshooting skills, then unmanaged VPS is the way to go. Note that while you purchase self managed VPS, you should be capable of managing applications, software, services installed on your VPS. Also, you must know installation/uninstallations, resource monitoring, server performance tweaking and troubleshooting of any technical issues.