I'm looking at buying a humminbird 698 ci hd si.  Does anyone have any experience with this one.  And what are some pros - cons.  Thanks 

Have not personally used one, but I know what it does and how it does it along with its features.

It replaced the 598ci HD SI Combo and the 798ci HD SI Combo when those models were discontinued. It sort of combined those two.

Does the same sonar functions of both and every other number series SI unit before and since until the new Helix series with CHIRP, minus any connectivity to other units.

Con: it has a narrower display than its height. It is not what is best for Side Imaging since screen width is the most important feature for a Side Imaging unit. BUT is better than the discontinued 398ci HD SI Combo.

Pro: since it is a Side Imaging unit, any Side Imaging is better than no Side Imaging. The close-out sales prices are very good. Highest screen pixel density in the industry before the Helix 5 series came out.