I would definitely get a used one as you want to make sure it is a kind you are able to use with no problems. I mean make and model that kind of thing. I mean we ALL know down to the vehicle there are some that are better then others but then again it comes down to preference. I am sure the one I use may not be the one that my competition uses for several reasons from price to size.
I would rent and use several kinds to see which works easier for your company and then look into purchasing down the road. It may even be a thing that you look into which is easier to maintain.