Many of my clients use the Camtasia version for Windows, and Camtasia 2 for the Mac is different enough that when they say “just click this, then this, …”, it’s a pointless exercise because the menus are laid out differently.
Functionally speaking, however, Camtasia 2 for the Mac seems excellent to me. For basic recordings, it’s pretty straightforward to use out-of-the-box. Adding effects, markers, and other adornments is easy enough…especially after watching a couple of their tutorial videos. Those videos are excellent, but make sure that if you find them through Google that you’re looking at the Mac versions!
Camtasia 2 is one of the few programs I’ve encountered that I’m happy to support by buying and using it.
Aside: The Mac Air’s audio is a train wreck, so I use a Blue Yeti Pro USB microphone. Worth every penny if your budget allows it, and it’s just plug-and-go with Camtasia.