My opinion is that you should care about weight if you will be using it with a RV! I used my phone nav program once because it was 10 minutes faster than the RV-760 I had. I regretted it when I came up to a bridge with a 3 ton weight limit that the RV-760 tried to steer me around. Had to unhook the towed and then back on to a busy highway to get out of it. That was 4 years ago. I now pay attention to the same RV-760 that I had then. Yes it has told me to go left a few times when I needed to go right. Nothing is perfect. I've started asking camp grounds if GPS units have a hard time finding them. They know and are prepared to give directions. That has only happened a couple times while traveling almost daily for the last 2 summers, a total of 30K+ miles. I highly recommend that you get one! I also recommend the Garmin RV-760. They also have a new model RV-770 with a larger screen (I think.) Good luck.