“Optimus magister, bonus liber.”
With comma or without? 
Thank you very much in advance.
I suppose it depends upon your purpose. To me, the comma neatly supports the elliptical statement. In other words, no comma would be needed had you said “optimus magister est bonus liber.” But without “est,” the comma makes the statement clear. “optimus magis bonus liber” is, at least to me, just a little too elliptical.
However, if you’re getting a tattoo, I’d avoid the comma.
David
I saw it on the cover of a book once without a comma. On the other hand, it was inside of a logo of some sort, so that may not help you at all.