Brian, I have fished with both recently and I couldn't tell a difference in the amount of noise that each made. I am a MK fan but my father-in-law has the new motorguide wireless and will admit that it is just as nice. The universal sonar works flawlessly on the motorguide and the spot lock seems to do what it is supposed to do without the dreaded "circle troll/freak-out" maneuver. If I were looking for a new setup I would figure out what sort of shaft and thrust I needed and then go for the best deal $$. Unless you are running Hummingbird and want the IPilot feature then your electronics/trolling system shouldn't matter.