Emmett, I have an 859 DI linked with iPilot and love it. As a muskie fisherman the ability to follow contours alone is worth it for me. If the fish are relating to certain depth I can follow the contour with an offset and cast right to the proper depth. So if the fish are relating to 8 ft I can stay 50 ft off the 8 foot contour and cast to where the fish are without running the boat over them. The trolling motor takes care of steering, I can concentrate on fishing.
Others really like to use way-points and link them together to troll along. For instance the walleyes are hanging in 12 foot at a specific area on the contour you can set a couple way-points and work back and forth between them.
Have not used this with a Helix but it should work the same.