I've only had my livescope for about a month and probably only been on the water less than 10 times with it. So far I'm loving it for knowing exactly what depth my gear is trolling at. Now, instead of dropping my gear and feeling for the bottom I drop the gear and stare at my LS and watch it go down to the depth I want it at. I'll also adjust depth as I see fish.
Another thing I like is validating fish marks. Sometimes there are so many marks on the 2D screen that I've found myself questioning if any of them are actually fish or just grass. With the LS I can better understand which are fish (big or small) or which are nothing-burgers.
Last night I was tired of getting skunked on salmon so I pulled out the bass rods and used the LS for targeting smallmouth. Again, I'm new to it, so I didn't have supreme confidence that what I was seeing on the screen were fish or not, but seeing what I thought were fish convinced me to stay in the area and keep working on my presentation. Sure 'nuff they were smallies and we did well on them. It was nice to feel a fish on the line!
My opinion, I don't think Livescope will make a big impact on salmon fishing. I think I'd still fish my gear in the same place, just get it there differently. Seeing a fish bury its nose in my baits is cool, and I like knowing that at least I got a sniff. Personally I prefer that over dragging all day and having no idea if the marks were fish or if any of them even showed interest.
Is it worth the money? I mean, come on, we're fishermen. This is hobby that is as cheap or expensive as we want it to be. Nobody complains about the guys buying a $300k boat or a bank fisherman plunking. To each their own and whatever you want to invest in your hobby is your business.