Which one of these is the best, in every regard.. Such as, price.. workingness.. and.. overall goodness.

1. Conair Dental Water Jet http://www.walmart.com/catalog/product.do?product_id=1956622

2. Waterpik Ultra Dental Jet System http://www.walmart.com/catalog/product.do?product_id=5740917

4.Conair Interplak Deluxe Dental Water Jet http://www.walmart.com/catalog/product.do?product_id=2599692&findingMethod=rr