depends really on how they are compared. if you do like russel marine and do a disingenuous "stare and compare" helix mega si+ versus a 93uhd with a gt54 in a green color pallete, then yeah, the helix is superior. but when you compare it to a gt56 on an ultra uhd or gpsmap head then they are very close. thats the one reason why i dont buy or recommend russel marine to anyone. if they are doing that on a freaking yourube review no telling what they are doing business wise.No need for livescope. Garmin 93sv for down image and Hummingbird Helix 9 for side imaging. Hummingbirds SI is far superior to Garmins SI and Garmins down image is far superior to Hummingbirds. JMO
just for yugoz and giggles, here is a guy's shot of an 8616 and a gt56 on fontana lake in nc.