The GT's have a dedicated down element whereas the CV's blend the side images to obtain the down view. Similar to what HB did, or does, on some of their models. Personally, I have the GT52 and cannot honestly tell you from my own experience what to expect. One of the guys on BBC (has some nice results) is ifishinxs and he has both, uses both and states he cannot tell a difference. Especially in water less than 30'. Rickie has posted some displays and charts that show how it works. I'm not recommending anything to someone, nor defending anything, nor trashing anything. My late friend had a Bird with blended down view. We fished Wappapello. Found a lot of stuff and caught a lot of crappie. All I can, or will, offer.