I tried to dump some footage into my Mac today and noticed it was taking a lot longer than usual. I checked the status of the 1394 connection in the options menu and is states the transfer speed as S400.

I've been looking through the manual to see if there is a way I can change the speed manually on the camera, but haven't had any luck finding anything. Has anyone else had this problem that could give me some advice on how to fix it?

I had those experiences in the early HVX200 days, but make sure you use a good quality Firewire cable. You might be getting the connection at 400mbps but the connection could be noisy. If you find a cable with noise guard thing around the cable, use that. After I started to be careful about the cable, I experienced no issue with transferring.