If you're getting an empty, digital, hollow sound, you ain't doin' it right my friend!
I would suggest you "walk a mile in my shoes, etc" and after a few years of playing the piano, you'll hear the difference. No different than analog vs. digital.
But IMO, the main difference to a real piano is - by far - the PA system, which always fails to reproduce the natural frequencies as they would come out of the resonating body of the piano.
Rosetree.......you nailed it right there. There is nothing that will ever equal the sound of that hammer hitting the strings, the string vibrating and bouncing off the soundboard,and the sound waves then entering your ear canal. It's an acquired sensation. I play both arranger AND piano now, but I remember when I first started learning the piano, I ignored the arranger for a while. When I went back to it, I heard a hollowness in the electronic instrument simulation that I never heard before But you can't deny the analog vs. digital analogy.
Kawai has some digital piano's that have a real soundboard in there..
Digital Piano's like yamaha cvp have a specially created amp and speaker system that allows the. To come closer to a real piano sound then an arranger currently does...
Same goes for the montage... Their A/D conversion has parts that make a piano sound more naturall ..
And then there is the high end VSTs like pianoteq that are not sample based, but are a mathematicall model that calculates the sound
There have been done some tests where people where asked to tell the real piano's from the digital piano's and most musicians and most had a hard time doing so...
Yet still people have preferences in sound, i prefer a Steinway or Fazioli over a Yamaha sound grand... Current high end digital piano's are that good, that its a matter of prefference what sampled model to use...