Hi Ape. I use the Mac all the time, and frequently record video. I've not done it with Quicktime though, as Apple sunset that ages ago. You should have iMovie on your Mac too. Do you know what version of the MacOS you are running and what version of iMovie? The menu options change every so often.
I'm not sure anyone has mentioned this in the thread, but the way the Axe will be setup by default, and the route that will give you the least latency when recording over USB, is to use the Axe as an interface / sound card. To set this up on the Mac you need to go into system prefences, sound (on the Mac). Set input to AxeFX (it should be available to select if it is switched on and the drivers were installed) and select output to AxeFx. This makes the Mac treat the Axe as the sound card rather than the internal. Don't worry, when the Axe is powered off, or disconnected, the Mac reverts to internal settings.
Now that the Mac and Axe are setup such that the Axe is your sound card, all audio from the Axe and the Mac are routed through the Axe. To hear it, you need to either connect powered speakers to the outputs on the back of the Axe, or my preferred method, plug a set of headphones into the Axe. Now any audio playing on the Mac will come out the earphones, and anything from your Axe will also be on the earphones. You can play along to backing tracks, you can monitor recordings, etc.
Don't be tempted to enable software monitoring on the Mac side, it will just cause massive latency. Use the Axe for monitoring. When you are done recording and are happy with what you have, turn off the Axe and the Mac will default back to its own speakers. All playback will be back through the Mac.
Fire up iMovie. Click import on the top button menu. iSight will fire up and a record button is present. It should automatically listen to the AxeFx because of the sound input changes you made above. Just record, edit, have fun. I don't find iMovie as intuitive as it once was, but it is free and does the job. I am running iMovie 10 on Yosemite by the way. It's not been uodated in a while so hopefully you have the same version.
In regards to firmware updates. It's straightforwards. First, unzip the firmware file you downloaded so that you have the syx file. Next start Fractal-Bot, then choose your device in step 1, browse for the firmware syx in step 2, and click begin. Wait till it's complete on the Mac, then wait for it to complete on the Axe, eventually it will ask you to power of for 5 secs and power on, wait for that message as the Axe does stuff after the Mac finishes.
You will find after updating that the Axe sets the USB level internally to 0. This needs to be turned back up. It's in the IO settings somewhere. The firmware release notes explain it I think. There's also a sticky in this forum.
You can also refresh the presets in the same way. You should as a lot changed. Note however that the presets still aren't that impressive.