i am considering buying a hds 5x gen2 or a hds 7 gen2. I know the screen on the 7 is larger and has a gps, but I already have a hand held Garmin gps 12. the difference is over $400 bucks. Is it worth it? I may purchase structure scan in the future, but not right now.The unit that I have now is a x 510c. Buying ether of these units will only mean changing out the head I could buy the unit without the transducer but I will not have one to sell with the 510. I like the HDS 5x since it is the same size screen.Can someone with this unit tell me what to expect or how they like this depth finder. Thanks for any comments.