Key feel ABSOLUTELY influences my perception of sound as I play. Whether the audience knows it or not, is not the issue. The way I feel affects the way I play, and if the keys don't bite back a little, and hit bottom with a solid thump ... it changes my approach. This topic comes up often on this forum, and you'll get many opinions, but for me ... it's not just the lightness or weight of the keys that I judge - it's the stiffness, the wobble, the length, the throw ... so many factors, and sadly, Yamaha and Casio are the two worst offenders in my book. Unless you go with a Tyros (or maybe Genos - dunno - haven't touched one), you get the lower end keybed, and for me, it's unacceptable. Casio ... don't even get me started. The pianos are "OK" (noisy, after time), but the synths are dreadful.