We bought a new Lowrance HDS7gen3 earlier this year to replace the Garmin that came with our new boat. I sprung for the structure scan transducer so I would have side-scan and down-scan. It was worth the extra $100. The ability to actually see what your sonar shows is invaluable. Trees, rocks, man-made items (concrete blocks, cables,etc.) all show as what they are. Side-scan can tell you which side of your boat the items are. Then you can mark it with a waypoint to avoid hanging up your downrigger. I've hung up on trees in 100 ft.+ of water down 40 ft. , shows it very well! Fish are a little trickier to I.D. with side-scan, but you can see baitballs with the downscan. Chirp is more sensitive then 200 k for frequency, medium seems more sensitive then high chirp. I haven't used ALL the features, but it's nice to have them as I learn the unit. I strongly advise anyone looking for more insight on reading bottom finders to look on Northwest Fishing Reports forum under boating topics for the thread called "sonar interpretation". It's a long thread, more detail then some will like, but skim through for info you need( I avoided the math and STILL learned a lot!). Buy it with the structure-scan transducer to avoid having to pay for TWO transducers. It's only a difference of $100 as mentioned earlier. I think we paid $1100 on line, much pricier at Cabela's (just about everything is, unless it's on sale or in the bargain cave). It loses detail as depth increases, but I consider it a valuable tool. We had a Lowrance 527 with GPS 15 years or more that had the temp. sensor in the transducer crap out, they sent a new tranducer without even having to send back the old one, the 527 plugs into the new one's set-up so we have a back-up unit. Customer support has worked great for me, help with installation and accessing and understanding features has been very good. A side note, you have two transducers with this unit, spacing and position is important. Hope this helped, Bob R
