Joined: Aug 2016
Monogatari is a series of light novels, not a manga. The only manga related to it is this thing, which is a completely inconsequential addition to an event that occurs in Second Season.
To answer your question - I'm buying the novels, and while they are great in their own right and the story arcs, characters and conversations are equally as compelling, the anime does such a great job at elevating all that through the tools the audiovisual medium provides that I see no reason to recommend the books over it.
So, my take: watch the anime (broadcast order works fine, btw), and then, if you like it, give the novels a shot for a broader experience.