I currently use the 5900 and I do pretty well with it. I have found over $120.00 in clad in the last 3 weeks. I also have found 9 sliver coins in the last 2 weeks which some were found pretty deep. These came from both parks and private homes.
Its a great machine, my only complaint is the weight of it. It hurts my shoulder after 2 days of heavy swinging, more than 6 hours a day. Other than that its perfect!