Nvidia GTX 1080 vs Quadro M4000
Hi Rob,
Ok, so everything below is based on my opinion:
I would go for the GTX1080. I also have the M4000 on my office PC, mainly because my company IT department tend to go with what suppliers recommend even if they do not work on the software on a daily basis... Why wouldn't suppliers recommend the Quadro's? Their profit margins are higher with a Quadro spec'ed workstation.
My feeling is that Quadro cards work well or rather are their money's worth in a Visualization Department. I recently had to spec three setups for the aforementioned department and they are happy with the results and speed (With Quadro Cards only because they didn't want GTX cards)...
I'm also going to contradict my last statement by stating that I also do quite a bit of Visualization (Stills, Walkthroughs etc.) on various Visualization software packages and I'm very happy with the performance which I get out of 2x GeForce GTX 760 in SLi. (Old'ish home setup).
I also feel that my setup with the 2x GeForce GTX 760 configured in SLi outperforms my office PC with the Quadro M4000 installed. (I mainly work in AutoCAD, Revit, Navisworks and with various Visualization packages).
I'm quite confident that you'll enjoy the GTX1080 and what you get out of it. PASSMARK LIST for high-end GPU's. The other thing is, Quadro cards tend to have a very slow decline in price opposed to GTX cards, so purchasing another GTX1080 in a year or so and configuring it in SLi will be an option too.
Long story short, I would go for the GTX1080. I wish suppliers could "lend" you/your company GPU's for testing so that you can fully compare the cards on the software which you use on a daily basis. 
Hi Rob,
Ok, so now your question resulted in me considering an upgrade at home. 
I started to do some digging apart from my original opinion.
THIS POST with professional benchmarks speaks volumes regarding the GTX1080's performance. (For me at least)... The area where it lacks is in SolidWorks, as SW is known to prefer Quadro cards, which doesn't bother me at all.
The point below which I found also puts my mind at ease:
"If you were running OpenGL design apps, you would already know the benefits of the Quadro. Long story short, it is optimized drivers. But this is happening for specific applications.
Don’t bother listening to ppl guesstimating or quoting AutoCAD performance…Autodesk products like AutoCAD, Revit, 3DS Max etc have been reworked for a looooong time now to use Direct3D instead of OpenGL, negating most of the benefits of a Quadro card- not that Autodesk was doing much work to coordinate with nVidia or AMD to begin with.
Especially AutoCAD has been outpaced so much by modern GPUs, that even build-in IGPs in laptops have no issues. Most glitches are due to the graphic engine of ACAD, not the graphics chip or drivers.
Double floating point precision (FP64) is nothing that affects graphic performance, so again, unless you want to compile such code exclusively, it is irrelevant. People that don’t already know they need FP64, should just ignore people guesstimating t hey do need it or that they might need it in the future."
THIS POST which I found under the forums Visualization section pretty much leaves me with no choice to stick with a GTX. lol...
If I was doing BIM coordination for the entire project, and needed to walk groups through the overall facility, then yeah - you'd need the massive VRAM only found on the high-end Quadros. But for modeling work, you would be dealing with small, workable models where it wouldn't be a huge difference.
If you are going to fly by the seat of your pants, expect friction burns.
"I don't know" is the beginning of knowledge, not the end.
