VPS hosting offers unique and identical IP, Operating system, database control, panel etc. to each customer and you do not have to share same features with others. VPS comes in two forms- managed and unmanaged. Managed VPS gives you unlimited bandwidth services and you personally no need to spend time for managing your website. Again unmanaged VPS do not take the full responsibility to manage your site.
Dedicated server is superior to VPS. This focuses only on a particular website. This is a physical server that allows you no sharing, own operating system, own control panel, mail accounts etc. You can go for dedicated server when your business reaches to such a level where it requires highest level of bandwidth, RAM and security.