Amiga apps and games will NEVER be compatible with AROS unless re-written and obviously only a small percent of those programs will ever get re-written. That being so, AROS (in regards to the retro Amiga experience), must and can only take place via emulation. Thus AROS's main highlight is the fact that it is a means to emulate Amiga within an Amiga like environment, free of the presence of Linux or Windows. That's my current attraction.
MorphOS on the other hand, can run MANY Amiga programs without emulation, and at speeds that far surpass emulation speeds even on high end AROS compatible hardware. This is an edge that AROS will not have until PC hardware begins to make giant strides in speed at an affordable (disposable) price. Though, for the time being, AROS does have the JIT edge, which MorphOS currently suffers without for it really needs it to be able to play that pile of software which can not be run natively under MorphOS. Of course JIT is being ported to PPC so time will change all...
I am sorry, but you are just wrong on so many levels.
First and foremost, ALL the solutions you mention have to emulate 68k software if not running on a Motorola 68000-based architecture! That means all of them except AROS-68k. MOS and OS4 do not run on 68k processors. AROS-68k however, runs Amiga software natively.
MorphOS and OS4 are both _emulating_ the 68k programs. The difference is that you do not notice the 68k emulators, called Petunia and Trance respectively. But to say that it is "without emulation" is just plain ignorant.
Now, AROS also has a "transparent emulator" project going on, called Emumiga. It is not done yet, but to say that it never will happen is wrong. When it is done, AROS will have exactly the same transparent emulation capabilities as OS4 and MOS, if not better.
These transparent emulators are only useful for system friendly software making AmigaOS API calls only. If the software uses the Amiga chipset, one has to use a more complete emulator in the form of UAE. Here AROS has the edge. OS4 and MOS both have to run an UAE emulator instance detached from the system, pretty much in the same way as when emulating real Amigas on Windows or Mac OS X. It sits in its own window, replicating the screen of the emulated Amiga, and does not interact with the host operating system.
AROS, on the other hand, has something called Janus-UAE, which allows all the Amiga chipset dependent software to be integrated into the system pretty much in the same way as with Petunia or Trance. That is, the HW banging software can use native AROS windows and screens, it can use AROS skins/decorations/gadgets on the 68k software, it can share the clipboard with AROS, screendrag etc. It is integrated in the same ways as modern Virtual Machine software uses "coherence" mode with the host operating system. It is a very cool solution, and maybe OS4 and MOS will get something like it in the future too.
So, I think you have to rethink your stance on "emulation", "compatible" and "NEVER". I am very happy that you are interested in the Natami project, though.