Better to invest 2-6 hours trying various instruments than in reading a book.
Agreed, except perhaps inasmuch as a book might help explain to someone lucky enough to have experience only of real pianos what all the features in the brochures mean.
-- sounds like a piano
This has to do with the quality of the sampled sounds used. You definitely want one with recorded samples for each note, not a synthesizer.
Are you sure? (I don't know myself, and am just expressing a gut feeling about how technology should have evolved by now). Synthesis has (or jolly well should have) come a long way from the Mickey-Mouse junk of a few decades ago. It seems to me that a system which is only
based on recorded samples is doomed never to sound anything like a real piano except when playing just single notes. Part of what makes real pianos sound the way they do, surely, is that there is acoustic interaction between undamped strings. This means that a piano playing (say) a C-E-G triad doesn't really sound much like what you get by mixing the recorded samples of C, E, and G being played on their own. A sufficiently sophisticated synthesis system, on the other hand, ought to be able to simulate the resonances which the strings induce in each other. Am I naive to assume that technology has come far enough to have this level of sophistication? Or is it still prohibitively expensive?
... a digital ... can only tell what velocity the key was traveling when it was pressed down.
Well, in some sense that ought to be enough, because the speed at which, on a real piano, the hammer hits the string is going to fully determine the sound you get. But it's not quite as simple as that, because on a real piano the resistance of a key to being pressed is affected by the complicated mechanics of all the levers and linkages involved, and is not just a matter of simple inertia. The response of a real key is non-linear, and the force exerted on the key by the finger even after it has started the key moving is going to have an effect. So simply sticking more lead into a key isn't really enough.
-- 88 keys
-- not unnecessarily heavy (I suppose this might mean "does not have amp and speakers embedded in it").
More keys means a heavier instrument,
Well, yes, but surely the keys, even if weighted, don't dominate the weight of the instrument.
And, to respond to Stu's point about embedded speakers, isn't this requirement contradictory to "sounds like a piano"? Speakers and amps are central to what the thing is going to sound like, and if you're going to rely on external 3rd party speakers, the sound is going to be essentially unpredictable.
Ultimately, as when shopping for an acoustic piano, it will come down to which piano is most enjoyable to play while still remaining in your price range.
Yes. It rather depends on what you want it for. If you are, for whatever reason, such as moving to a smaller house, getting rid of a real piano and replacing it with a digital, you may want to be more careful about what you're letting yourself in for, whereas if you are keeping your "main" piano and are only considering a digital as an additional instrument, for portability such as when visiting a friend who has no piano, or when going camping or sailing, you might be prepared to make some compromises.
One thing I'd find worrying is potential lack of longevity. If something breaks in a real piano, you can easily get it fixed, even if the piano is 50 or 100 years old. If something breaks in a digital that is only 5 years old, it may already be obsolete and you may not be able to get parts for it, and have to throw the whole thing away.
On the other hand, you never need to hire a piano tuner, and you may be able to experiment with different temperaments, or press a few buttons to make it sound like a harpsichord or an organ, or even a harp or a carillon.