For my 2cents worth you should steer clear of the combo units unless you have backups for each. When I was setting up amy new 20'center console I thought the combo unit would be good because of the limited space avail. It's not worth the downside. My experience with my Garmin GPSMAP125 unit which has seen 4 trips back to Garmin showed me that if I had my gps die in the middle of a peasoup day, I could at least use my depthfinder to correlate bottom info to chart location. When the one unit has both functions, you are really blind. This year I'm adding a separate sounder and perhaps a hand-held backup gps.