I decided against the Helix units when rigging mine last month for a couple reasons:Not only was my dash pre-cut for the 800 & 900 series humminbird, I wanted to see how the Helix line holds up to moisture and vibration after a year or so. The legacy units are proven to be very durable and still give a great service, far surpassing what many of us are capable of getting out of them, or ever needing from them. I ended up settling on a 999SI at the console and 959DI at the bow. I also like being able to fit the bow unit in the recessed area, eliminating the need for an extra mount, as well as keeping it low and out of the way of my un-coordinated size 13s.If they hold up, and I still want to upgrade, I would definitely consider a Helix with chirp for the bow. To me, that is the only left to be desired by Humminbird, sonar that is competitive with some of the other brands.