A VPS is essentially a medium between a shared server and a dedicated server. Several customers will share the same physical hardware, but rather than sharing one operating system, each customer gets their own OS installed.
From the point of view of the customer, it appears as though they have their own dedicated server, but in reality, they don’t. Another benefit is that web hosting companies typically only put a few customers on each physical server (depending on the hardware specs of the server). Since the customer has their own operating system installed on the server, they will enjoy much more control over how it is set up and operates. Some key benefits of a VPS are significantly less expensive than a dedicated server. You have your server control panel so that you can typically install any web application or other software as your need. You also reboot your server anytime you would like.
For many people, the VPS is the perfect solution for running sites that either need more resources, or more control than a typical site normally would. Since you can negotiate the exact technical specs you need, it is possible to operate sites that get a high amount of traffic, while still saving a lot of money. The only potential downside is that you may need some level of technical understanding if you want to make specific changes.