The Helix Mega units have a transducer that produces almost 1.3 MHz of power to produce a true pic on the head of the unit from the transducer as I understand it. Hummingbird advertises 3 times the power. I have to say this, in the muddiest, garbage filled water, it gives the best image I have ever seen. As I understand it,( not a guru on electronics lol) all other units, the head of the units, take the pulses from the transducers and computer generate the pics on your screens. Garmins a very good unit and lots of reads in the electronics section of the forum. Lowrance has very good units and they just did a software upgrade that really created a better pic on DI of my TI 7 that I also run, it really did a outstanding job on their carbon series units. For the money, a lot of guys are going to the garmins and I went for the Helix Mega 9 SI at 1300.00 as their 10 is 1700.00 but has I think even a better picture cause it has 400 more pixels in the screen, but the 9 is so super as it is, blows me away with the clarity. You can add panopix on the garmin, real time fish movement, and on Hummingbird you can add the 360 but both are a chunk of coin and always more money. Same for the top of the line hummingbirds and Lowrances, as it’s a matter of how much do you want to sink into electronics? The way I saw it, at 68, hope this is the last electronics I ever need, but heck, are we ever satisfied with our toys? On,the front of my boat, I run the Mega 9 for DI and SI and a Lowrance hook 5 to show lake map and sonar. Back of the boat I moved the Lowrance TI 7 HD SI and DI. It’s a G 3 jon for walleye/ crappie fishing or trolling out of the back. I spend all my time tho crappie fishing on the front, so constantly run a split screen on the 9 of SI and DI. It works best for me. I run my front transducers attached to one of Rickie’s (Podunk Ideas). Da Ducer. Best way to decide on which electronics to purchase is go to a store like Bass Pro or Cabelas, and play with all of them in their demo mode to decide what yo want as well as read in the electronics section of the forum. Also, you can go to Bass Boat Central, and read the pros and cons there of each unit, but when it come to tournament fishermen, they are always going to go for the best but you still get good reads and opinions also. Good luck on your choice if you upgrade as lots to choose from.