I am a HB owner but do not have your model. The 581i appears to have the larger screen of the 700 series, and most of the features with a B&W screen. It should be a decent gps/sonar combo.
I'm saving up for the same one.
I dont know anymore than what you can read on their web site.
But like stated above, its got the most features for the cost. B&W is good for me.
