In the end it really just comes down to personal preference. NURBS vs SubD, 7th degree curvature continuity, making changes to adjust for client request. “Speed” is relative and workflow/project specific. There are times when making a certain model will need whatever tool is needed to get to the end goal. You’d no sooner use a drill press to try and cut a plank of wood…right tool for the right job. This is the area where I feel like most designers fall short (or maybe the finger could be pointed at the company) for not knowing the full range of tools that should be available in a designers tool set. It’s defacto that a company will have the Adobe suite and at least Sketch Up, Rhino, SW…(insert CAD software of choice). What is rare to find is company adding in say Houdini, C4D, zBrush or Modo in to the mix which, at first glance having some of these other software tools may seem like too much, but if viewed like a traditional shop then this just makes sense. But this does an another layer of complications on a multitude of levels, I get it, not saying it doesn’t complicate matters, but the options possible brings more to the table. Add to the fact that there is never enough time to actually properly evaluate and/or implement any of these other tools which does make it that much more challenging.
There’s another thread here about creating a displaced surface onto a piece of geometry and the idea of Rhino and Grasshopper as the solution, if the question is about speed, is the absolute wrong way to go in this specific instance. zBrush would knock that out in like 1/10th the time and Rhino/GH but most designers won’t know or have the knowledge or skills set with which to even know either the possibilities and/or capabilities to execute that workflow.
…bah I’m off on a tangent here but hope this at least begins to make sense to some.