Double duh It is the best but should be used in conjunction with other anti virus software, Malwarebytes will catch everything that other scanners cannot reach like some rootkits and so on, but like all the others it is not perfect, it just has better coverage in the difficult to reach areas.
As a mac user I've always been concerned about protection as I've never believed the whole Macs-never-get-attacked myth. I only have Norton installed but tend to be cautious.