Andy Shipsides at AbelCine has posted a great workflow primer on ingesting C300 MXF footage into popular NLEs:
Update – 2/14/12: Since I wrote the above Canon has provided two plugins, one for each version of Final Cut Pro. They facilitate ingestion of Canon MXF files into Final Cut Pro. Both plugins support the C300, XF305, XF300, XF105, and XF100 video cameras.
XF Plugin for Final Cut Pro v1.2 is for FCP v6-7.03 and it is Lion compatible.
XF Plugin for FCP X v2.0 is for FCP X and it requires both FCP X v10.0.3 and Mac OS X 10.7.x.
To access either on Canon’s site you need to select your operating system in the drop-down menu within “Drivers & Software.” The XF Plugin for FCP X only appears if you select “Mac OS X 10.7.”
Update 7/4/12: Canon C300: FCP X vs. XF Utility for Backup/Archive
Update 7/3/12: C Notes