A VPS, or Virtual Private Server, is best described as a "slice of a pie".  The Host Node, or "pie", allows for multiple slices to utilize it's resources.  Processors, or CPU Units, RAM, and Storage are all housed in the Host Node, and each VPS takes a 'slice' of that overall set of resources.

LXC, or Linux Container, based VPS's utilize the Host Node's Kernel as a core system.  They are limited to Linux-based Operating Systems, including, but not limited to, Debian, CentOS, Ubuntu.  They share resources between other Linux Containers, while maintaining the the ability to spike to full utilization of the container.

KVM, or Kernel based, VPS's utilize the Host Equipment to establish completely isolated resources, dedicated resources, that improve security, responsiveness, and functionality.  They include support for installing your own Operating System from an ISO, or utilizing pre-built templates that we have available to you, for your core install.

Unfortunately, until we know exactly what you're wanting to do with your Virtual Server, we cannot make an informed response for your circumstances.  Between our LXC and KVM VPS's, the KVM VPS's have more functionality and versatility; however, it also comes with an increased cost.  Our LXC VPS's have reduced functionality, but are more cost effective for new projects.

As long as the processes you're running on your VPS fall within our Terms of Service page, you should be good to go.  There are a few key items to note in the Terms of Service page are Section 3 - Acceptable Use Policy and Section 4 - Blocking of Bulk E-mail, Spam Tagging, and Virus Protection -- Specifically section 4.3 in reference t Outbound Mail.