In 2014 I finally sat down and made myself learn Zbrush hard surface sculpting after many failed false starts. Now I use it for most of my modeling.
It is the most tricky UI and it is not really like the other 3d applications. I can model in Softimage, Maya, and Modo with the same level of competence as they all have the tools required to follow Vitaly Bulgarov’s Gnomon disc in Softimage.
Zbrush has many little gotchas. They are specific. They are like little english lanquage exceptions where a rule is used except for those twelve exceptions per usage case.
After fighting with it for hard surface I finally had the ah hah moment and all the different workflows lined up like that scene in the Dark Crystal when the three suns meet and beams into the eyes and all the different parts made sense as a whole. BUT… it was a bit of a battle.
Mudbox could easily be more relevant if it had a hard surface workflow like Zbrush and then added a way to do a zremesher type or retopo that is based on curves or previous brush stroke history.
As of now the only part I lament in Zbrush is retopo time when getting what I want from Zremesher isn’t going to cut it. One time I must have run Z remesher using Zremesher guides about 20 times with different settings before it actually did something close to what I wanted.
IF mudbox or Zbrush came up with a preview/interactive slider showing a guesstimate of the general polyscale and flow results you were going to get while you were playing with sliders it would be immensely helpful. I often use polygroups and zresher curves stroke by polygroup edges and do decent. But its the last little hangup in my hard surface workflow.