I'll only say that my own advice to whoever want to read Kazantzakis is to read Report to Greco and nothing else. When I read it my reaction was "why did I bother reading the others", not because of its superiority but because it is a mash-up of all his other work. It's like reading an anthology. You get what the fuss is all about and you don't waste your time with the rest.
Other than that, I find his tone deliberate, like he wants to write in epigrams, his women are caricatures and lesser creatures, even for the time (of course in real life he was considered a gentleman and very pleasant company) and this mixture of early 20th century mysticism, German philosophy and eastern quasi-religion is not very original and definitely dated (and too close to what gave birth to certain ideologies that messed up the 20th century). He is an elitist and completely ignores common people (despite his proclamations to the contrary).
Overall, if you take out the mysticism, he appears to have all the negative traits that I - and many other Greeks- associate with Crete and Cretans. The μαγκια and κουτσαβακισμός that one can see when one considers for example the case of Zoniana and other such moments of brilliance from the island, the superiority that we are constantly reminded of thanks to the flattery of Crete in media and political discourse in Greece- which I think dates from the time political parties realised it's a crucial electoral area etc etc.
Zorba the movie is an improvement on the book, because at least it concentrates on the positive and cheeerful stuff (more or less).
Anyway, if you are interested in Kazantzakis the man, it might be worth reading his first wife's Galateia's fictionalised account of their time together, Ανθρωποι και Υπεράνθρωποι. I've only read part of it, but it's an unflattering portrait, written 30+ years after their divorce. In it the protagonist is a man who seeks admiration above all. As always, I think the truth is somewhere in the middle between his self-prerception and what his wife observes.