I just went through this process. I decided to spring for the full ETO package
instead of buying things piecemeal. After fretting about the fine print for
several hours, I decided to rest with the authority of people who've already
decided what's "essential" for Mac development, and so I bought ETO. At first,
I balked at the price. (I've paid $1K for DOS Metaware C and Pharlap in the
past.) But I haven't regretted my decision so far… the sight of our code
compiling cleanly on the Mac has made up for any past hesitation. 🙂