Just for changing the oil in my inboard boat it was worth more than the cost.  In addition, no more turning small engine over to drain oil.  Just be sure the oil is up to operating temperature.  Also, on some rigs it can be a bit tricky to insert the hose to the bottom of the pan.  It works great on my 5.7L Chevy, 6.0L GMC, 4L Jeep and the Camry.  Took a bit to find the bottom and not over shoot my son's A4 Audi, but then again that car is horrible to work on in most every other way.