Mounting is not a big deal either way. The main advantage is that on the transom, the sonar is showing what you already passed over. On the trolling motor, you see what is right under the boat. In recreational fishing, it is not a big deal. If you are a bit more serious or competitive, you will have an edge. Especially with down or side imaging. As for damaging the transducer on the trolling motor, they make transducer savers. They work very well. I am the very abbusive on my motor fishing these south jersey mud puddles. I recently bent my Fortrex 101 shaft and broke off a prop blade on a stump. Transducer is fine though.
