I have purchased one but not installed it yet. The only reason that there is a need to install quadra beam is becuase of people install the si transducer in a spot that will be out of the water on plane. Most are doing this to protect the investment in the si transduer, a replacement one is 200 bucks. I would only install in a location like that if I fished a standing timber lake. You take a good chance of knocking it off. I plan to mount it in a location so it will be protected, I have a flasher to use will on plane. So I dont have the need for the quadrabeam. I do have a quadrabeam on a 37 on the front they are a nice transducer. I like the option that gives you the typical depthfinder view and the top looking down. If you dont know there is a yahoo group called sideimaging its worth the look at, lots of info on the all the si units.
Ted
Neither snow nor rain nor heat nor gloom of night will keep me from crappie fishing!
2010 Lake of the Ozarks Super Slab Champion