Fishhawk X4. The old 840 was not the best unit. The X4 is a huge upgrade from the old 840. Depth Raider, Subtroll, and the Fishhawk X4 are all quality units. It comes down to personal preference. I went with the X4 because I did not want to deal with coated cable, antenna's on the rigger and bigger probes. The X4 also has sealed electronics. If it gets water in it, it will not die like the other brands.