I LOVE my old lowrance x67c. The new one i have is the elite5 chirp. A couple things really bother me about this unit. 1. The Scroll speed is too slow and choppy and there is no way to increase it. 2. I have not noticed a single change to the display interference when using the noise rejection feature. 3. Why although the chirp shows detail better then regular sonar it also shows more clutter in the water column than normal sonars.
A couple weeks ago i was fishing in the same shack as a Marcum lx7 and a vexilar fl8. The chirp was pretty much worthless, but the x67c hardly showed any interference.
Maybe i got a bad unit but i dont think so. There are threads on other forums complaining about the scroll speed, and there is a video on youtube showing the clutter i am talking about.