A Dedicated Server means just that: there is a physical machine which is dedicated to hosting the website and email of a single customer. Obviously the advantages of this are that you are not in competition with any other websites and you can configure the server any way you like.
But maintaining a server machine means a commitment of time and resources. You get none of the benefits of a shared hosting environment where a professional company is monitoring and maintaining the physical and software environment for you.
The other disadvantage is cost. Having access to a Dedicated Server is the most costly way of hosting a website and email. For this reason it is not suitable to the majority of small businesses or individuals.
If you feel you might require a Dedicate Server, please contact us and we will review your specific situation and advise you on what your best options are.