Like you, all I ever had was b/w 2d sonar. Heck, I even used a flasher now & then, up until 8 or 10 years ago !!

I purchased a Lowrance Elite 5 DSI from a member ... and now I'm totally sure of what is within the sonar sweep of the DI, and not trying to interpret a bunch of b/w blotches or relying on "fish symbols" to (maybe) tell me there's fish around me. I get a picture-like image of what I'm going over, so the guesswork is gone

I was a total newbie to this technology, so I started a thread about my unit in Nov 2011 ... to get some help with the learning curve. The most recent post was made in Mar 2015 ... after 86 pages of discussion & info sharing. Much of that info may be of some benefit to you, especially the charts & diagrams, and possibly more.

I am of the belief that SI is most useful for "scouting" areas, especially on new lakes or areas of your local lakes that you're not too familiar with .... and possibly even some areas that you are quite familiar with. Lake bottoms are not static ... they're constantly changing in varying degrees. Whether it's silting, cover being placed or moved, or shifting sand bars ... what's down there last year may no longer be there this year, and something new might take its place next year. That may mean that a certain spot that you used to fish without much success in the past, can end up being a honey hole ... after you've given up on it.

Getting your unit set up, installed correctly, updated, and any of the other "learning curve" situations you might be confronted with ... can usually be solved by simply letting the fine folks on this forum know what the deal is, then wait for them to reply back with the solution. It's what I did ... and I'm appreciative of their help, and continue to try & pay it forward by helping pass along what I've learned from them & from my experience with my unit.

I totally understand the sticker shock that comes with the latest/greatest technology that's out there ... I went for around 40 years using $100-$150 low to middle end depthfinders, only to use them for the simple function of telling me how deep the water under me was. My $475 for this Down Imaging unit was a momentary "trigger shy" moment for me, too. But, now that I know better how to use it, what it is capable of, and how to make the functions work for me ... that outlay of funds seems way less of a deal than it was when I was writing the check !! The more I use it, the more a bargain it seems to have been. (and I say that & believe that, even though Lowrance has discontinued that particular model)

... cp