Track up Vs. North Up. Some people have a hard time with North Up and prefer Track Up. Keep in mind that when it is set to North UP, the map image stays relatively constant and the boat direction icon moves. With Track Up, the boat direction icon stays fixed pointing straight up and the display is forced to keep re-rendering the entire map. This can get blocky depending on how quickly the graphics processer can keep rendering.
I have a Raymarine Display for my Radar and GPS. I find it very difficult to run in Track Up mode. It takes a second or two to re-render the map, so it makes the display look like seizure inducing Japanamation. If you run with North Up it more closely matches the charts. Your mind gets used to adjusting for it. Now when I look at Track Up, I'm used to the orientation of the paper chart and find myself thinking 'what the heck am I looking at'.
Track Up is the default for cars, but I prefer North Up on a marine chartplotter. This is just one persons opinion.