It will be interesting to see if we get some replies from those that have used both.
I’ve wondered the same myself, but to a point it may depend on what head unit you already own. To get the Mega 360 or the new Humminbird Live, you need a G3 or G4 Helix, meaning lots of guys would have to buy a new machine to run the 360 or new Live stuff. If you already own a 7 or 9 inch Garmin from the last couple years, you’ve got the head unit to run Panoptix or Livescope already.
I have Humminbird G2 units in my boat, one being a 12″ SI G2N I got for a good clearance price this spring. I’m not about to go out and spend what it takes to replace that screen with a G4N to run the newer Bird tech. I’d honestly probably be more likely to buy a 9 inch Garmin for $600 right now, sell the SI transducer, and then upgrade to one of the Panoptix transducers.
If I had a G3 or G4 I’d look harder into the Mega 360 or new Bird Live.
Since I bought a Garmin 73cv for ice this year if I wanted to upgrade I’d consider looking for a used regular panoptix transducer for a decent price if they exist. Not looking to make that investment yet though.