Quote - ...Which one is the "best" or most widely used?  Why?

That's a hornet's nest.:biggrin:
Ask 10 people, get 10 different answers.
Maybe ask for advice in the 3d modelling forum. There are many different modelling apps being used in there, so you can get some different perspectives.

If you just want to use the premade figures?
Then all you would need is Poser.

Friends don't let friends use booleans.