I have a MG Xi5 and love it because it stays within 1 foot of where I spotlock it. The 'new' MK's have supposed to upgraded their spotlock but you have to add another external gps puck to make it as good as the Xi5. I think they are $300/400 more as well.
Whatever you chose, if you have an issue mounting these electric steer trolling motors (hitting the bow roller, precariously mounted on the edge, etc.) because of how they hang off the boat, please take a look at the following product to address these issues. The LiftSaver Trolling Motor Mount works on both brands. Just click on the website link or the TFF post in my signature to learn more.
LiftSaver Trolling Motor Mounting Bracket - Patent Pendingwww.liftsavertmmount.com
Works with MG Xi5, Xi3 and MK Terrova, Ulterra, PD V2 and Riptides as well.