Looking for the right fit GPS/Fishfinder

[Polar2003]

I have a 19ft CC that I mostly use for shallow water fishing, and a lot of tricky navigating requirements to keep from running aground.  I currently have a Garmin 468 w/sounder that I want to upgrade to a newer model.  I am looking for one that has better naviational options and better graphics and mapping details.  I would like to know if anyone has any feedback on the Raymarine A50 series units.  I would also like to know if Navionics are good software charts?  Thanks for your help on this.