I've been running my FF800 for years with a 2007 MacBook Pro, a 2006 iMac which was replaced by a 2012 Mac Mini, all of which have FW800 (9 pin) connections. More recent computers and Hubs/Docks generally only have the 9 pin FW800 connectors, and of course Apple makes the Thunderbolt2 to Firewire 800 adaptor, which other posters in this forum have endorsed as being a solid option.

I run both my current machines with MacOS 10.9.5 as well as Windows 7 Pro SP1 via BootCamp (since my primary DAW is Pyramix, a Windows only application). The Fireface with RME's most current drivers connects seamlessly to both operating systems (although I did have uninstall the standard 1394b driver in Windows 7, to replace it with the provided "Legacy" 1394b Driver).

I read some time ago that it's a preferred method to run things in a chain: Computer -> Firewire External Hard Drive -> Fireface 800, although I did run for a few years using the FW400 connection for the Fireface, leaving the FW800 connection for my Media hard drive. My newer computer only has the FW800 connection, so I'm used to running the computer-drive-interface chain.

The main issue is the flimsy Firewire connector, which has no latching mechanism to hold it in place. I'd recommend that you run with the shortest cable length you can manage, while still allowing enough slack in the line to put no stress on any of the connections. As long as you are careful about this, it's a rock solid connection.

I would suggest that you look for good quality brand name cables, such as those from Belkin or Tripplite, which can be found on eBay or Amazon.