I realize this is an old topic but thought I would add my 2 cents worth as I was just searching "PX-5 keybed noise". I purchased my Px-5s 3 years ago and have in general been satisfied with it. I have gradually moved away from using onboard sounds and now use the PX exclusively as a midi controller. I've gotten much more serious about playing piano and have been taking jazz piano skype lessons for about 6 months. This has resulted in my becoming more aware of the sensitivity of the keyboard. The Px-5's velocity response for soft versus forceful strikes is pretty good, but I have become increasingly dissatisfied with how noisy the keybed is. It wasn't any issue when I was playing the PX in a band scenerio but solo, the noise is distracting. If I wear closed-cell headphones it's not a problem, but who wants to wear head phones all the time? It's to the point that I am seriously considering selling the PX and purchasing a good midi controller such as the Roland A-88 or Studio Logic SL88. I've also been looking at the M-Audio Hammer 88.
Any thoughts a bout alternative midi controller keyboards with decent (and quiet) hammer action?