What's the real benefit of a flushing unit over a deluxe?
I'm planning a corporate gathering for about 150 people, lasting five hours outdoors on a grassy field with catering. The rental company is giving me two options: a deluxe-unit and a flushing-unit. The deluxe unit has a non-flushing toilet with a larger holding tank, plus a small sink with a foot pump for handwashing and a mirror. The flushing unit has a foot-pedal flush that sends waste into a smaller holding tank. The flushing unit costs more, and I need to justify the expense. The ground is level and there's good truck-access for the weekly service visit. Does the flush make a big enough difference in guest comfort for this type of event to be worth the upgrade? Is the smaller tank on the flushing unit a problem for a five-hour event?