I too have a Terrova and also love it. Even if you have Lowrance sonar, they make an adapter connector that will allow you to use the unit's US2 transducer. If you can't live without your Lowrance DI, there's also an easy way to install the Lowarance's transducer cable down shaft. I have both and normally just use the 2D imaging of the US2 transducer.
Unlike Medic I am old and my back is worn out, so I'm saving up for the new Ulterra.