I have never used one with all the graphs. I am planning on buying one for my kayak, but not sure what features I need. I am wanting to see structure and fish mainly. What other features should I want?

What do you consider "structure" and how do you want it displayed?

 

Look at the Screenshot post at the top to see what technology you would like to have.

If you want sidescan, the HB Helix is a good inexpensive unit.

 

Best to be moving for good sidescan. Not you how well that would work on a kayak.

I have the Helix 5 and it's a nice little unit  I originally bought it for my seaeagle inflatable pontoon ,but then mounted it on my aluminum boat, heres a couple of pics 

Raymarine Dragonfly. 4dvs ($250) or 5dvs ($300)

 

Chirp sonar and down vision. No GPS

 

Pro model adds GPS/maps.

 

Side scan not available