MorphOS is just an another nostalgia OS for these with Amiga past. Another ones are AROS and modern AmigaOS, but these currently has no usable Mac ports.
It's main feature is a 68k JIT translator for fast running of an old Amiga apps together with native ones. I doubt it will emulate an old Amiga chipsets though, so app base is limited. And that's all. Sure if you're not for that, you may still like it , since it is very polished, esp. its UI part.
However, imo their dev team chosen a wrong way. Their product is neither open-source nor free. And license is pricey. You may still run it in a demo mode if your PPC Mac is supported, but this means you have only half an hour to work with it, after which it enables slowdown mode, which is totally unusable, means you need to reboot the OS to make it good again
Afaik there is currently no known illegal way to bypass this.
I personally think it's simpler to find a combo deal ofused PowerPC Mac + MorphOS w license, with good price on eBay or Amiga related forums than to buy license separately. Or one could find an old Genesi Pegasos (II?) computer which will allow to run modern AmigaOS together with MorphOS, which is more win - and also frees Mac to run what its supposed to run, i.e. Mac operating systems