Dedicated servers are for medium to Large Business.
A dedicate server is a single server dedicated to a single customer. Most appropriate for users that require lots of disk space or data transfer, as well as sites that are database intensive or have specific software requirements.

Dedicated servers let you control the entire server and Reseller is a part of a server.

Dedicated server is better, but if you don’t need to many space and bandwidth as with dedicated server better use Reseller or VPS as well.