I have owned a number of fishfinders, especially in the last 5 years.
I had a humminbird 798 and 898. (5" and 7" screen) with sideimaging. Sweet rigs!! Would buy either of them again in a heartbeat. 5" screen was ok, but 7 was ideal.
Then I saw the lowrance touch units and wanted one of them!! So I bought an HDS 12 Touch. Had it over 2 years, love it. Perfect for the big striper boat. Great 2d sonar, 3d charts, sidescan downscan, great unit!! HUGE screen!! Can run maps, 2d sonar, and sidescan at the same time and still see what is going on.
I have a humminbird Helix 5 with Down Imaging on my jet boat. It is a sweet unit!!! Crisp sonar, just doesnt have GPS which is irritating for me!!! Other than that, they are around $225-250 on ebay and are a great unit for that price.
I really appreciate side scan for these shallow rivers around here and would love it on the jet boat. I just dont want to bust a $200 transducer on a rock!!!
If I had to do it again, and mix affordability with luxury, I would CERTAINLY get the lowrance 7 TI. It is a 7" screen, preloaded with maps, touchscreen, chirp 2d sonar, sidescan and downscan. Best price that I could find on this unit was $699. I think you can get em with just downscan for $599.