In a dedicated server you will get full hardware node but in VPS you will get a virtualized machine, a machine that seems to be independent but will have other VPS running on the same hardware node. VPS tries to emulate the environment of a dedicated server through software. End of the day there are still a few users in one particular hardware. Its a good transition from shared hosting, unless you go straight to true cloud.

Dedicated server is basically one user to one hardware. Generally bigger companies would favor this for control and data security, compared to vps.

Both emphasize privacy of data but dedicated offers a more complete version.