I've used it on three projects thus far--no problems. One note (that caused a bit of panic).
If you are ingested directly from cards (and X is open) the camera import browser launches immediately as soon as the card is plugged into the computer. However, if, like many shoots, you are copying the cards first to drives and then later, after the shoot, ingesting from the drives, the import browser needs to be invoked from the file menu (import from camera). Then, and this is important, select "camera archive" as your source. You will then navigate to the drive and folder where the card media is and all will be well.
That caused a heart attack until I figured it out. The point is--the import browser only launches automatically with actual camera cards. It sees everything else is an archive.
And FWIW, the C300 is a great camera!