Kid,

I picked up two of the HB 998 models last year and love them. Have owned Lowrance my whole life, but decided to give HB a try. No regrets. Love the units. But, I have not used the new lowrance at all so, can't comment on the differences. Just looking at all the info out there, they appear very similar, and you probably can't go wrong with either. The SI, and DI is really nice, but requires a learning… I am still trying to figure out what the heck I am seeing a lot of the time. It is just a totally different image.

I like em both, and have been milling it over for a while. My buddy wants to sell me his new HDS 7 for the price of an HDS 5, so its kind of another option for me.
The only thing I like about one brand over the other, is that lowrance's menus have always been easier to navigate, and little things like turning on the backlight and dimming it. Maybe HB has fixed that, but its something worth looking at.