In order to see the difference between dedicated servers vs. vps, you have to know if what those servers are for. Dedicated servers are intended for clients who have huge websites which also have high traffics. This server is preferable because of its bandwidth as well as performance. In point of fact, most web hosting companies which offer dedicated server are more established and large, compared to any other hosting companies.
The difference between vps and dedicated is that with dedicated you are the only person with files on the server. VPS is a virtualization environment where everyone gets root access inside a virtual machine, but there are multiple people with these VMs on one given physical server. If you are comfortable managing your sites in a VPS as root, then it won't be any more difficult to manage them on a dedicated server.
Virtual Private Server (VPS, also known as VDS or Virtual Dedicated Server) hosting is an ideal solution for users who need more power and flexibility than a shared hosting account can offer, but need a low cost alternative to a Dedicated Server.
VPS hosting solutions are virtual servers functioning within a single physical server. Thus multiple Virtual Environments (VE's) are operating on one the server at any one time. This does bring about greater user customisation and performance of service delivery when compared to shared hosting, however dedicated servers still boast the fact that all resources of the server are available for the user to fully customise and employ however they should wish.
Hosting of Dedicated server is a better variant for those, who would need reliable and stable solution for large web projects or aplications.