Advice requested for a new site...

Hi,
Thanks for taking the time to read my request.

I want to move a website I have already in Joomla to WP.
The construction I want to have is:

- a main website where I offer some services (administration and websites installs, etc)
1 . some sub-sites/domains with sites examples with different themes and colors. Where people can have a look to a final designed website I offer to make.
2. kind of shop where customers will be able to buy services and website design services.

So my question ...
Is it better to have a multisite construcion?
or
1 base site plus some sub-sites/domains?

Cheers,