3 channel marine amplifiers are only offered by JL Audio. JL makes these 3 channel marine grade amplifiers in two different series, with completely different price points and applications. The MX series 600 watt 3 channel amplifier is a solution based amp that has a completely sealed design and was originally designed for the powersports industry. The M500/3 is a full size, 3 channel marine amp that offers some of JL's leading Class D switching technology. M500/3 is going to sound significatnly better than the MX600/3 despite have 100 watts less of power. If you are looking for sheer volume and you aren't worried about signal processing, the MX600 is a great choice. If you want fidelity and great sound, the M500/3 is the way to go. If you want a 3 channel, and you want JL, but you can't afford the M500/3, the MX600/3 is still amazing and you will not be disappointed.