I use the heck out of this tool, probably every week.  I've had it about two years and haven't had a lick of trouble.  The on/off switch on mine has worked without complaint.  The speed control has also been reliable and is a nice feature on occasion to lower the speed on more delicate items (although I usually run it wide open).  I don't really have much complaint about the vac attachment; mine wiggles loose sometimes, but not every minute (if anyone honestly knows of one that doesn't every come loose, feel free to buy me one for Christmas; I think it's just the nature of the beast).  Dust collection (with my Fein vac) has been excellent, especially when sanding wood.  I have almost no clean up after.  I've also used this for some moderate drywall work (remodel stuff) and it's been up to the task.  That generates a little more dust than can be controlled with such a small tool, but I was still able to capture about 85%+.