I have had both the Minn Kota Terrova (Gen 1) and the Xi5. The spot lock on the Xi5 was much better than the Terrova. Although the odd time, it would glitch, and spin one way wanting to rip everything out as it couldnt spin anymore lol. There was an update of sorts that fixed that. I did have to replace the transducer, that was $400. On both Terrova and Xi5, had the seal go requiring the lower unit needing to be rebuilt due to water intrusion. Thankfully this was covered under warranty.
If I were to to pick between both now, I would definitely lean towards the Terrova as the spot lock was greatly improved. It also has lift assist, the Xi5 can be a nuisance to stow, especially if choppy out. The Xi5 remote is very basic. I also like the autopilot feature on the pedal, which is missing on the motorguide. The pedal on the xi5 also isn't great, and may require some modification.
I no longer use either. Moved to an Ultrex, and then onto a Lowrance Ghost to tie in with my finders.