I had a 50/200 with my older Furuno, as Rolmops does. Loved it. I now have a Hummingbird with the standard transducer that came with the Helix 9. I have notice a slight drop off when searching at a higher speed and sometimes loose bottom. Never had the issue with the 50/200.
Not sure if that is the specific reason, but seems to be a difference.
Dave