This is the first time a new guitar or bass needs no big setup, and I own 19 of them, plus all those I owned before. The nut's notches are cut neatly, just the right width, and just the right depth. The saddle has precisely the ideal height, too. Intonation seemed to be off by a lot, but after adjusting the truss rod and stretching the strings, only four of them are off by one or two percents. That's tolerable for now, because I want to enjoy my new guitar, and keep the filing for later.
It's only a matter of minutes to remove a tiny bit of material from the saddle to make those strings 1/3mm longer. The action, overall, was very low, and barely buzzed, so I made the neck's bow a little deeper, and that's it. The fingerboard and saddle base were very dry, had to oil them twice over two days, but that's okay now.
The strings have precisely an identical spacing at the nut, and the spacing between the two E strings and the neck's edge is the same, and wide enough so the skin of the hand does not accidentally mutes them. The sound is very loud and shimmering, and those Adamas strings are very rich in harmonics, even when tuned down because they are thick for my fingers (these are 12-53 and I need 10-47).
The body's ergonomics are very good for my leg and my shoulder, same for the neck overall. I only made it less sticky with a kitchen sponge. I don't own an acoustic amp now, but the tone through an electric amp is very nice, that's promising. Fortunately, the neck's heel is well contoured, and I can finally play my usual tunes on the high frets without having to switch on an amp.
The top's halves are very well matched, and the assembly, inside and out, is free of imperfections, I checked with a flashlight in the interior. No buzzing from poorly glued bracing or whatnot. The saddle is ideally contoured for my hand, playing those muted notes is natural.
The keys are fine, not super finely responsive like Grover, but tuning up or down has no slack and no frustration. The small reduction in responsiveness compared to Grover's might be due to too many windings, I'll know when I change the strings in several months. For now I give them the benefit of the doubt.
The on-board tuner is accurate, and confirmed by outside tuners. I didn't like the first generations of piezo pickups, they sounded plasticky, but this is a piezo that sounds natural. I have to insist that the unplugged sound is very strong, and rich. Harmonics at the 5th, 7th and 12th frets are very loud and sustainy, and only great wood does that.
The aesthetics of the wood's fibers on the sides and back are pretty, and they match. The abalone inserts are cut without any gap or imperfection, and they shine beautifully. Several screws and nuts had to be tightened a bit, that's to be expected, and not annoying. By the way, I don't play with a strap, so I removed the strap attachments, and left only the golden screws for looks, the attachment at the neck hampers the hand a little when reaching for the high notes. But it can screwed at another place for those who wish.
With picks (Ultex) or bare fingertip skin, the guitar is powerful and shimmering. And the low action from the factory is THE big plus, for once I can play anything immediately with comfort and no fatigue. I used to believe in uncoated D'Addario's only, but after hearing those coated Adamas in person and upclose, I want to try them on other instruments.
And finally, the jumbo name is deserved, unlike some acoustics that only have the shape, this one has the bass-rich jumbo tone, too. Yes, this guitar can be advised for acoustic and amplifier players.
Edit: I removed the thick plastic pickguard and its thick rubbery layer of glue, after what the tone gained some clarity. If you still want one, it's easy to make a neutral pickguard with thin transparent adhesive film; it protects just the same, doesn't dampen the sound, and is replaced quickly.