The MBAM-Mac-1.0.1.7.dmg installer downloads and installs as quickly/well as any other app. The on-demand scanner uses/downloads signature file version 4. Actual on-demand scans of a MacBook Pro of recent vintage is quite fast finishing in 24-30 seconds if nothing positive is identified. YMMV.
I don't have any available test files, nor do I know the breadth/depth of the black list yet. I hope we will know more after the honeymoon is over. If Malwarebytes Corporate reputation is the current deciding factor, I would certainly recommend installing MBAM for Mac.
Hopefully the base application and associated signature files will be rapidly updated when/if required.