Great units but there are problems when you buy NON-supported equipment. Besides what Wayne P. stated, none of the newer transducers will work on the Gen1 (HDI, TotalScan, 3D module, etc...etc..). I would suggest getting the Gen1 and use as a stand-alone GPS and this will allow you to maybe get a larger screen, current family, sonar unit like the Hook or Elite-TI. Don't let the touch screen scare you. I have never had to wipe my hands before the screen would work, but, it's nice to keep a soft cloth and eyeglasses cleaner close by.
Of course, if you plan on having a unit at the bow and the console, networked to share info, you will need to step up a little.