(GOOD)
The dial on the 55 is huge. Also has independent zoom. Both nice features.
FL22 excels in shallow water conditions. It is also super sharp and crisp with the readings compared to other brands.
LX-7 give you both vertical and round read outs, something no other brand offers. Independent zoom also.
(BAD)
55 has two cables for the ducer and uses blue on the flasher for the 3rd color.
FL22 only goes down to 60′ and zoom is set at 6′, 12′ only
LX7 is larger and does not fit a 5 gallon bucket. More fragile compared to other flasher.
I have not experienced any feed back issues with any models side by side. Each brand has adjustable power levels so you can play nice with your buddy next to you.
Obviously you can’t go wrong with any of the new electronics but it just comes down to what you want and need.