DHCP User and Vendor Class

If I understand DHCP user class, means if you want some workstations in the network to be able to use specific router as their default gateway or specific DNS server as their server, differently from other workstations, then you can define new user class in dhcp and you give it a display name and ASCII name, then on Scope options/Configure options/click Advanced tab, in user class drop down arrow, select the user class you have previously created, then select the checkbox for DNS server or Router you want to assign to the class and in the IP field type the address and click OK…

That 's the DHCP server part, then you go to workstations that you want to assign the specific DNS server or router, and do the classID configuration.

My question is ,do you do it the same way for vendor class? in which case you use vendor class? how it is different from user class?

Any help will be very much appreciated.

Thanks