Is hard surfsce modelling for this kind of mech a lot more tedious in zbrush compared to something like maya or 3ds max? Or would you say its easier in zbrush
Both have their advantages, in my opinion zbrush hard surface modeling like he did is very good to conceptualize a design really fast. Will you have clean topology? No, but you can create in a very free flowing way by not being bound to topology, all you care about in the moment is the shapes, no technical stuff.