Not piling on. This just seems like the right place to add my experience.
Through 2012 my camera was a Canon 450D. My process was to Calibrate (CR2 to fit), Debayer, Align and Integrate (all as fits). My Bias, Flats and Darks were fits.
I'm now having to dust off the Canon while my CCD goes back to the manufacturer for cleaning. With my modern Flats, Bias and Darks in the xisf format, the CR2 Lights will not Calibrate. However, a BatchConversion of raw to xisf first does then allow the Calibrate to run.
Not a deal breaker, just one more step in the process.
Great software BTW!
Mark