If your a serious competition fisherman, most any decent sonar unit should work. When I started fishing, it was just go wherevthe packs were, then I learned to watch out fir charter boats, then came flashers, then moved up to your basic sonar depth/ fishfinder and used these up until just recently. I bought a used boat that has modern electronics. I have been reasonably sucessfull when fishing, never big on getting my limit, just out to enjoy the fishing experience and the day on the water. If I didnt do well, it was a good reason to go back out another day!! I know have a Lawrance Elite HDI which is over 5-6 years old but new technology to me. It is awesome to see what is down there, but....has it made me catch more fish ??? Nope, yes it has upped my chances to catch more but no electronics has ever made the fish bite. I know how long it has taken me to learn how this thing works and I still have lots to learn after a full season of playing with it. Would I spend 600 plus to upgrade...no way...cant catch enough fish to make it worthwhile...but that is just me. A decent electronics unit helps to locate fish and lets you know when an area is barren but none makes you catch more fish. If I have a bad day of fishing, I find that as a reason for going back out another day!!! Looking back thru all my 60 plus years of fishing lake erie, cant say for sure that all the fancy electronics I have used over the years have put any more fish in my cooler, so.... does having the latest and best electronics on the market mean more fish in the boat ??? Have to think hard on that one,.....