To some it means upon setup you tighten the bolts in one position and need tools to adjust. Unless you drive with just your eyes, you need a tractor that has easy to reach steering wheel, foot pedals and controls. Since you will be driving over grass and round obstacles most of which are bumpy, look out for tractors that come with free hemorrhoid creme. High back seats are the best. Look at the construction of the controls.
Plastics are fine as long as they are protected.
Look closely at the front axle as well as the ease of sharpening the blades, checking oil, air filter, battery, and filling the gas tank. Ask yourself if you will be happy in 3-5 years with your choice. Ask for other customers that have purchased similar units. Great yards start with great care. Try this simple yet effective 4 step program.