Select.. I'm not sure exactly what you mean by the comment "lowrance won't work with Terrova".... are you refering to the universal sonar? If that is the case then lowrance will in fact work with universal sonar. I have it on my boat as do many of us. Just a short lead jumper (made by Minnkota) that plugs directly in to the universal sonar cable coming from the trolling motor. In the lowarance menu you select the correct transducer and you are set. If running multiple units, you network them through an LSS structure scan hub or a standard ethernet cable and you can utilize either transducer from either device (front or back).
If however you are refering to the use of following contour lines from your map, then you are correct in the sense that Lowrance will not work. Hummingbird is setup with the Link system that operates through the terrova trolling motor and the use of a Link remote.
I've had both the motor guide and the minnkota and although both are good trolling motors, motor guide has a long way to go to catch up with the functions of minnkota. In my opinion, motor guide is way behind in regards to spot lock, auto pilot, and navigation. After a day of fishing in my tournament boat with the motor guide, I was ready to throw it in the water due to the constant beeping every time you hit a button to change direction or speed on the trolling motor remote. Minnkota doesn't do this.
His current setup is a Powerdrive unit however, most have reccomended that "when" he decides to switch, he switches to the 24v terrova.
I have OCD "Obsessive Crappie Disorder"