A1 will get the best support for games since Hyperion continues the development of Warp3D. AOS 4 will come with UAE for older games.
Hyperion is a company with limited resources. It's yet to see if they can alone develop an OS and port games in paralell, and supply their solution with applications alone in the meantime.
MorphOS already has a very nice WarpOS/Warp3D support via wrappers. I can play Shogo (a Hyperion game) anytime on my Pegasos - can you do the same on OS4? No. You have to purchase it once more, in the form of a "native" version.
And it's not everything. JunGL is in development for some time and will provide full OpenGL support for MorphOS. Do I have to explain it's expected impact?
Not to mention UAE 0.8.22 which runs happily here.
We have plenty programs which were developed natively for MorphOS and later had AmigaOS versions as well. This is the way how the community indirectly benefits from MorphOS development.
With Pegasos/MorphOS you get free SDK and the SuperBundle.
With AmigaONE you still get nothing but a Linux with UAE. (Sarcasm on)With "buggy" drivers, which can't support ArticiaS features, thus corrupting data in some cases.(Sarcasm off)
If all goes well, you will soon receive a pre-release of OS4. It will have (according to forum posts) neither WarpOS/PowerUP support, nor native Picasso96, JIT...
For quite a long time the two solutions will be no match for each other. And if you want to wait for a full comparison, you may have to wait for years.
You can get frustration on both systems. The difference is with AmigaONE you can expect to have a hell a lot more for much more, and far less on Pegasos II - for almost half the price.
Another slight addition: MAI northbridges are present in the AmigaONE and the Teron. Both are MAI products... Many projects which used or planned to use the Articia northbridge folded, or switched to another one.
While the Marvel northbridges (one of which is used in the Pegasos II) was recently chosen by IBM as well.