First, and I'm not sure why more people don't ask the additional questions with regards to electronics, what graph do you own already? If it's Lowrance/Simrad...then look at the saltwater version of the Motorguide Xi5. I'd not get the autodeploy model for saltwater. I've had too many friends have problems with them due too corrosion from salt water. I have the Xi5 on my bay boat and fish upwards of 35 miles offshore on calm days. It's an absolute game changer...my anchor hasn't been out of the locker in the last 9 months since owning it.
If you own Garmin Hummingbird electronics, then I'd go with Minn Kota. Minn Kota integrates with Garmin Hummingbird and Motorguide with Lowrance/Simrad. The ability to control the trolling motor via the graph is very helpful in bass fishing. Minn Kota has an advantage there for following a trail, while Motorguide, it will follow specific GPS waypoints and trails you set up. Motorguide has a more precise spot lock. Neither Garmin or Lowrance trolling motors offer a saltwater version yet...so if it were me, I'd hold off on either of those.