I think this comes down to a matter of opinion.
I have a Buzz Pro and wouldn't exactly call it good for a "rough environment". The voltage adjust wheel has a good size opening so dust and debris could get into the circuitry. Other than that, it's pretty tough.
The Provari has the led and window that I'd be afraid of breaking against something at work. That's all I can say about the Provari.
The Darwin is out of the question for a rough environment by everything I've read about them.
Btw, I chose the Buzz Pro due to that voltage wheel. I like to be able to adjust on the fly without clicking through menu's and such. Simplicity can be a good thing.
Another "IMO" is to look into is a Reo Grand. That can take plenty of abuse and it's a self contained juicer. My Reo's are usually my work and travel mods. VV is the only thing they lack but that's due to be incorporated soon.