Haven't heard anything on the Helix, but over the years I've learned a few things. Don't scrimp on your electronics and trolling motor. If your a dedicated crappie fisherman, I think those are the 2 most important pieces of equipment on your boat. I have 2 HB 999s on my boat. One on the console and one on the bow. Yes there are better units out there, but there comes a time when you draw the line for what you need vs what you want. SI is a great feature for scanning a area for the first time and marking structure. After that I rarely use it. DI is great after you find that structure to see it in more detail. 2D sonar it is what it is. When selecting a unit, make sure it will allow you to use a SD/micro chip in it like the Lake Masters or Navionics Hot maps. Both the Lake Master and Hot maps give you valuable information about the lake and lake bottom. My suggestion is whatever unit you select, if your within a couple hundred dollars shy of the next unit up, hold off, save another couple hundred, and get the next unit up. In the long run you will be glad you did.
The one and only "Crappie Whisperer"
Vexan Crappie Fishing Rods, Humminbird Fish Finders, Xpress H20PFC w/200 V-Max Sho, Minn Kota trolling motors.