I also have one of the original Shark steam mops with the rectangular head, and I hate it. I have approximately 1000 sf of floor space downstairs, mostly hard wood. On the original Shark, the water tank is too small and the cord is way too short. Plus when the microfiber (terry cloth) head gets wet, it drags on the hard wood floor and requires a considerable amount of shoulder strength to push. I only use it when I'm ready for a workout.
The newer generation of the Shark mop has a larger water tank and longer cord. And it has a triangular head, too, I believe.
The only thing good I can say about it is that it does clean good, and it does a good job on textured vinyl floors (in my upstairs bathrooms), whereas my Ready Mop doesn't.