[villagetinker]

We have a convertible Yamaha 4 seater since 2013.
Advantages: can still use it for golf, with the seat up holds 2 golf bags, with the seat down we can have 2 additional passengers. Over the last several years we have only used the rear seat maybe a dozen times. The cart is only 3 inches longer than a standard cart.
Disadvantages: We had to add additional brake lights as the fold up floor blocks most of the original taillights. The suspension was modified for the additional seat, and therefore we have a stiffer ride. If you have 2 adults in back the steering can be a little sloppy.