Helping my grandfather look for a new sonar unit for his boat and he seems to like the price/features of this unit. Wondering if anyone else on here has one and has anything to share about it. Likes/dislikes? One thing I have to look into (probably from humminbird website) is whether or not this unit is acceptable for use in salt water. He was told that Garmin units are not sealed for saltwater use or someting? Sounds fishy to me (no pun intended) but I just want to make sure he's going to really like whatever he gets.