I currentlyhave a Hummingbird Locator, model 598 GPS with Down Imaging and Side Imaging on a color five inch screen.  I want to upgrade to a unit that has more current electronics and a bigger screen.  I have not found Side Imaging to be that useful when fishing.  My small screen does not do a good job of highlighting the sonar fish echoes.  Has anyone found Side Imaging to be helpful in putting more fish in the boat?  Is it worth the extra two or three hundred dollars on some of the higher end units?