2 year warranty on the hds line, 1 year on the elite. Hds hold more wypts & trails. Hds can share sonar, mapping, full wypt management and other junk that I've forgotten. Hds can use Ethernet and nmea, elite only has nmea network. Hds gen2 touch require no lss box. Hds gen3 don't have to have a lss box and give you chirp sonar & wifi.
But they all cost too much.