Right now, it's difficult to say that the Sabaj a30a is better than anything. I have been interested in it since it came out, but have never found any independent testing results.
There are reports of volume problems with its sub out, the sta516 chips in it are somewhat old, first coming out in 2014, and the amplifier is expensive.
The PFFB by Axign is intriguing, but I have read somewhere that the patent on that is expiring, or already has, and TI has that capability in some of its newer amp chips.
The Merus 5332MS in the SMSL came out in mid-2021, but i haven't seen any testing of the AO300 either.
So right now, I dont see how the a30a is "better" than the AO300.
And the AO300 is half the price of the a30a, so maybe that makes the AO300 "better" to somebody else.
And besides, I can get a Hypex amp from audiophonics that has been tested with great results, that is more powerful and for less money than the a30a, and not much more than the AO300.
For me, that's "better".