A common accessory is to add a hand wash sink to these port o lets, we found that though the sink is a great design with a large basin, easy access for maintenance, however they also have some defects, the main one is that the no kink drain hose which seems to be very low quality always breaks resulting in a costly purchase of a new quality no kink drain hose (after which the hose never breaks again). Because this hose is actually above the clean water tank dirty water can drain straight into the sink. Another issue is the soap dispensers, they're one of the worst I've seen as they leak soap constantly. It would have been much better to make the dispensers seal so they wouldn't spill.
Company: They've been very friendly to us for the most part, however we had an invention to improve their portable toilets (seat cover dispenser) that they past on citing that out of the USA these are not very widely used. We once had another manufacturer (Five Peaks) cancel our order though we had already rented those units out and had to quickly find another supplier, Poly John delivered on time and kept our customers happy.
Color choice recommendations: Tan, Light Gray, Aqua, we recommend a color thats light and appealing, this also makes the restrooms seem cleaner for longer increasing customer satisfaction. We chose Aqua however we now feel that Tan would have been better.
Here's a list of pros & cons:
Pro: Cost, these are very affordable especially for what you get
Pro: Attractive, these have nice curves throughout
Pro: Lot's of sign space, most manufacturers forget that we put signs on them
Pro: Very durable, the springs almost never break, nothing ever falls apart etc
Pro: The optional sink is easy to maintain and has a large basin
Con: The door is made from two sheets of plastic, if you accidentally push a sheet in it'll cave in and detract from the cosmetics.
Con: The holding tank can spill waste easily, so don't shake this thing around or mount it on a trailer
Con: The redesigned toilet paper rod is horrible, when you take out the paper the rod drops to the ground (we now use zip ties on the hook end to ensure it doesn't fall out
Con: The sink has a defect in which the no kink hose fails