Damn stuff changes so fast that it is darn near impossible to keep up and a lot of small things between makes and models. It is all about money and preference. I got a HDS 9 Gen 3 and you can jump up to 3d with the added hardware on it. Humminbirds 360 while weak on sonar display it can run the downriggers and you have a 300 ft 360 sweep for fish that is absolutely stunning in use. Frankly what I did was decide my top $ and researched what could fit my budget. One thing for certain the idea that a tiny screen is a good thing is bs as much as a big screen but down graded performance so I went with 9 inch Gen 3 and Skimmer transducer.