A big question before this answer would be what kind of budget you want or need to stick to. Then the answers will flow in like spring water. Personally as the others mentioned, I love my GPS chart screen as I use it on the front on ALL trips, every time. I fish specific locations quite often and that is important to me. You can follow a pattern or sit on a brush pile easier with the spot marked on your DF. The rest is what size screen, color or black n white, number of pixels, or if your wanting to link your units, or use the down/side scan imaging with your unit. Those type questions. Usually go for more than what you may think you need and you usually will be glad you did though. Just my 2 cents worth. Good luck to you.