I have 3 Lowrance, LCX 110, LCX 25 and a LCX 28 HD. All with sonar and GPS.
I fish the Chesapeake bay and tributaries for bass and stripers the most.
I love the color and the detail.
Here are some photos.
When you say "Fish marks" I hope you do not mean you want the unit to actually show little fish shaped symbols?