We use an Ultera on our 20' Lund and love it. We use it primarily as an auto pilot to steer the boat and use the kicker for propulsion accept in early Spring when we want to troll extra slow.
Yes they are definitely pricey. Also they are hard to find right now, I have friends that have had them on back order since last season and no word on when they will arrive.

Be sure to get the long shaft and preferably the 36V. $$$ more money for batteries. But IMHO well worth it.