Actually it's not a gimmic,,,i recently purchased one myself and had it out for the first time last saturday,,,i must admit it takes a little understanding of how it work and what your looking at considering all we have been looking at for years was just what was under the boat streight down,,this technology has beeen in the making for some years and almost every manufaturer of sonars has r&d working on it,,just humminbird has come out with it first is all,,,,Anyway i have found a few sites to get information from,,,one is just new started the other day,,
http://www.xumba.scholleco.com/
http://groups.yahoo.com/group/sideimaging/
whether ya like it or not,,,technology stops for no man!!
ohh ya side finder and side imaging,,,,,,not the same!