The guy I buy my stuff from (Gil@semperfi fishing on TheHullTruth) mentions reliability issues with Navico (Simrad/Lowrance) - never owned one. I have had a couple Garmin's over the last 20 years. No failures, but support has gone downhill a bit. Gil thinks Garmin has better CHIRP for saltwater (lot's of computer processing going on with CHIRP). For sounder use, transducer choice is probably more important than F/F brand. It all depends on expectations and fishing style - I am a mover; nothing going on, move. I want a F/F that I am confident will mark Salmon, just not bait balls as I have fished bait balls w/o catching Salmon.
I fished with David Murphy a couple years back; all his boats use Simrad CHIRP & we could see Salmon swimming towards the lure, so the Simrad stuff he uses works well but I doubt you will touch the stuff he has for under $4K.