thanks for mentioning those hi-re files. ... i'll listen to them ... am very interested in what i might hear .. .. i just tried casio privia's (the 150 which dealers say has the same key mechanism as the 350) .. was able to do this in two different shops. and also compare the 150 action against kawai mp6 (for further comparison.
it is cery difficult to hear a substantial difference w/pt with standard midi and hi-res. that said, the privia keyboard, when played softly w/pt receiving hi-res velocity does seem like it responds to touch in a more nuanced way. at soft dynamics, the sound (of) pt (w/hr midi) seems a little more articulate than standard midi. and the same when playing fast, articulate passages ... fir example, jazz eighth notes at a speedy tempo. the sales guy said that hi-res seemed just a little more lively as well. his impression was pt was responding just a little bit better w/high res.
the p-150 i tried has release velocity locked at 64. or at least that was the setting (release at 64) on the two 150's i tried. so i can't say from experience how release velocity influences sound.
comparing the kawai mp6 action to the casio action, i found the kawai feels like a very finely tuned mechanism. it's a little smoother and feels like it has more engineering. BUT .. i also felt - or i think i felt! - the lack of hi-def resolution on the kawai. which is to say that that nicer, more acurate keyboard on the kawai seemed still to lack in expressiveness compared to the privia.
overall, i'd say i was having a more interesting, engaging experience w/high res rather than standard midi.
well, that was my experience from this morning.