NOTE: When comparison shopping, please note we have a 45 day no hassle return policy. Also, other companies may be "drop shippers" meaning they do not even stock your product. Goodman's stocks and ships all our products from our own warehouse in Miami, FL. J2000 series are a bit more ergonomic for home garment steam use. M indicates metal steam head, which is a bit heavier, but stronger, and retains heat. J4000 series are commercial steamers, more powerful and larger water capacity, but not as compact and ergonomic.