Using a Mac for the most part, sometimes a PC. No problem with the ports when using my backup interface.
MOTU said they were pretty certain the MKIII has some sort of hardware failure. I was concerned because I couldn't find anything on the web about the error message I was getting from the MKIII. I'm sure it will be fixed accordingly.
It's been great, I bought it for the additional ins & outs, and you can use Volta
http://www.motu.com/products/software/volta/images/signal-path.jpg/image_view_fullscreen plugin which basically gives you CV control.
I'm just not crazy about about it crapping out this early on.
Oh well, it will give me some free time to work with the new MFB Urzwerg sequencer I just received.