The cheaper ones are usually closouts or else just don’t have all the bells and whistles on the newer more expensive ones. They all show the same information but you need to be able to read it. This comes with practice and by going over water you know so you learn to tell stumps,rocks,weeds,sand, mud, and most of all fish and baitfish. I use Eagle and I am really happy with them, but I have never used a Garmin. I am sure they are all basically the same.