Been out of the fishing game for many years after losing all in a garage fire. A trip to pymatuning last year reminded me of how much i missed the crappie and walleye fishing. So i bought a boat in the fall, and need to put a fish finder on it. My, how they have changed in the last 10 years or so. Last unit i ever owned was a fishmark480. I would love to put a larger screen humminbird on it, but i also have to spring for a trolling motor for the front. I thought i had it narrowed down to a HB 698, but today the nearby Gander Mountain has the HB 798ci hd si for 649.99 and a 50 dollar rebate. Figured if I liked si and di, in a year or two i would get a larger unit and throw the smaller one up on the trolling motor. It also looked to me that the 798 had a little wider screen to it. I guess what i really want to know, is there any real advantage the 698 has over the lower priced 798, or am i approaching this all bass ackwards, and look for a unit that may not be so complicated for a first time user.