Autopsy/SleuthKit in the courthouse?

I am studying digital forensics and have been working with both AccessData's FTK and Autopsy to analyze disks for different assignments. I keep hearing that Autopsy findings should not be admitted in a court of law due to a lack of proof of reliablity, integrity, etc. This is bothersome, as I find Autopsy to be the better option of the two digital forensics tools that I have used. I know their are other options out there like EnCase, but I really find Autopsy to be a nice system to work with. Has anyone here presented digital forensics findings that were derived from Autopsy or Sleuth Kit in a court of law, or found literature/precedence regarding this question. I see that Autopsy received early funding from the U.S. Army and currently receives funding from the DHS, so I have to think it is at least somewhat regarded as a professional grade tool.