I had them on my last I/O as well. It was a '98 Rinker 182 with a 3.0L 4cyl and Alpha1 outdrive. They were an excellent addition to that boat. Planed quicker, and allowed for a better ride overall. I think I might have gotten an additional mph out of it as well (It ran 42mph as empty as I could get it). They lasted me the few seasons I had that boat after installation with no problems. I had used their "trolling brackets" on my installation, but had mounted them "backwards" so that I could retract them when wakeboarding/skating. The tabs absolutely destroy the shape and size of the wake, so retracting them was important at the time. I think they're a great product overall.
I asked about them here when I purchased my '17 AR190 a few years ago because of my success with them on the last boat. I'm not sure which thread, or what the title of the thread was to even go look for it honestly. There were a couple of folks that had tried them, and the general consensus was that they were "too much" for the jets. The idea was that the constant deployed nature of the smart tabs lead to a constant bow down attitude (since there is no trim reasonably available for the jet) and scrubbed off significant speed. The Yamaha already rides so much nicer than the Rinker (despite comparable dead rise angles at the back) that the ride isn't really a concern. I'm in the middle of my 3rd season without them, and honestly, don't miss them much. I've yet to have the jetboat porpoise at all, and with the L13/Ribbon Delete, I have zero issues getting to planing speeds, even with heavy loads. If I was running around in significant waves constantly, or had a consistent problem with the boat listing with uneven loading I might consider some electric tabs that would fully retract when not needed. With my current setup though, I don't really have the need. I'm loving the simplicity of this boat over my last I/O, and don't really want to disrupt that any more than I have to with added things to adjust.
Keep in mind, the only evidence I have here is anecdotal at best. I'm not sure I've seen any hard data from somebody actually using them on a 19' Yamaha. If they work I'll be next in line to get some, if they don't then someone just drilled holes in a boat for the benefit of others. I suspect, like the great fin debate, that it would be good for some, and not for others.