I remember reading about fastar when it came out, it looked very enticing, I'm surprised that its take up has not been as big as I'd imagined, with such a low f ratio, its has a unique imaging potential.
Perhaps people don't like removing the secondary mirror and having to replace it and re-collimate every time they want to observe visually. Rob in the A & S shop demonstrated to me how easy it is to remove and replace it using the display NexStar 11 GPS so it doesn't worry me. There is always the chance too that that you may knock the projecting CCD camera off something and crack the corrector plate. Saw a photo of such an incident on the Internet. Also, Fastar is not suitable for many CCD cameras as they would block too much light.
Due to poor takeup, Celestron ceased supplying NexStar 11s with Fastar some time ago (only making these models for Starizona) although they continued it for the smaller aperture models till the CPC scopes arrived.
  