We're looking at purchasing a John Deere X580 or X584 or X590 w/ a 54" deck for my folks place. Will be used for cutting ~4 acres of grass & pulling a small trailer w/ my pop's lawn tools & to pick up sticks. Any of these better than the other, pros/cons of any of them? Is the 4 wheel steering on the 584 any good or just one more thing that can break? Thanks!