WordPress is easy to learn and to use, and mainly it is good for a not techy.
Joomla is easy for a techy.
At the end of the day the customers want to earn money, you can use even CodeIgniter, or PHP language. The meaning of best means:
- what is easiest for you
- where your brain works better with success
- what is making for you economy to time and a good name
- and more