The white ones have a few extra layers of paint, and the circut boards are waterproofed in an epoxy, or like silicone so they are sealed to keep the saltwater out. Maybe that's all the difference in Motorguide, but Minnkota ripties are pretty legit.
I have a 2017 Terrova riptide. It is amazing, long as you have a little wind or current, then the spotlock works perfect. Keeps me in about a 2ft circle, if it's almost dead calm, then it will wander a bit, but that's expected. GPS systems have a little lag, so they often react and over react, then have to adjust again to correct and over correct. with a little current it holds steady, because it doesn't have to do much left/right correction, just forwards and backwards. The Bluetooth functions are not really used by us, but they are nice to have, especially the jog feature, moving 5ft with the press of a button. I have fished mine at the beach in ripping currents and in lakes with slow current. I still carry an anchor, but it's only used if the current is pushing more than 3mph. I have the 80lb thrust and about 3mph is all the trolling motor can generate, so it wont hold in current faster than that. Driving from the back is the best thing ever when you fish from the back of the boat.
Fishing is a science, study, experiment, fail, and succeed...then start over tomorrow. Yeah I'm a science guy.
03 18ft Xpress Jon boat Center console 90 HP 4stroke Yamaha Humminbird 1199HD SI
97 14ft Polar Kraft Jon boat 85 Johnson 30hp Lowrance Elite 5 DSI