Ok guys I'm looking at finally adding some electronics to my boat. It is a 15' dual purpose boat, so no need for 2 units. Just need 1. Cabelas has this model on sale, (Garmin® echoMAP™ 73sv Sonar/GPS Combo with LakeVü™ HD), for $479.99 regularly $999.99. So my question is, is this a good unit and a good price, or is there a better value out there. The unit I use on my boat now is an extremely old hummingbird unit that basically just tells temp and depth.