I am sorry if I am a "off" on the subject, as I do not know about VPS or Dedicated Servers much. Isn't it really difficult to manage a VPS? How hard is running one? I'm sure it's not like just a reseller or shared server, is it?
I would like to know these things. I know I want to switch to either a VPS or Dedicated, once I have a successful hosting company.
Managing a VPS is pretty much the same as managing a dedicated server. Think of it as a scaled-down version of a server, especially if you do not need the full capacity of a full server but need root access or offer reseller's accounts.
The major difference between a dedicated server and a VPS is that for the case of the dedicated server, you have full access to the physical machine while a VPS still shared the physical hardware and network port with the other vps on the same machine.
Managed is when everything is taken care of for you (depending on the level of management). Security patches, updates and anything else a server would require. Unmanaged is when they give you the VPS/Dedicated server and just hold up their end of the bargain by keeping your server online.