I've been using Clarisonic for two years now, basically ever since I first got my hands on the Mia2 and did a review and demo here. I change the brush heads frequently, but the device itself hasn't given me any issues. If I don't use my Clarisonic for a few days I begin to notice little blemishes and my skin just doesn't feel as smooth as it normally does.
When I got my hands on the latest Clarisonic Sonic Radiance Brightening Solution, I was super excited to retire my older device and began using this one right away, and I am SO happy that I did.