In a previous job we had a Mazda BT-50 single cab, mainly for getting around the site.
It was quite nice to drive, partly because you've got windows all around you so visibility is good, like driving a car, and it was handy for getting a scaffold tower on the back. I thought it looked really good with a ladder on the back, like a fire engine.
Carrying anything else around could be a bit of a pain especially if it was raining - then you're largely restricted to whatever you can get in the passenger footwell. If we didn't mainly use it for driving around private grounds I wouldn't risk putting anything easily nickable on the back unless you've got a hard cover.
I wouldn't choose one as a work vehicle unless you're doing something or working somewhere specialist.