The M1 PX look to me to be 45 degree. I can compare the two and the U1 seem to have much more of an arc than the M1 PX.
The issue with the M1 is that apparently the power supply has an issue on one of the speakers. I believe it’s the step up circuit.
So not great options, and maybe why they’re both for sale I suppose. He declined to let me swap the panels from one to the other unfortunately to get the best of both worlds.