I know, but they were not made by the same OEM IIRC, and certain models of the AXi were known to go pop long before they were old.
No. The AXi was the replacement top tier PSU from Corsair. Sadly they were nowhere near as reliable as the AX series.
Not from what I have seen, no. I have seen quite high failure rates. IIRC (and don't quote me here as I am going from memory) the AX range were built by Seasonic and the AXi by another OEM. So they were completely different and not comparable to each other.
Because I guess Corsair didn't know they were unreliable? They're good quality units but failure rates were very high. So to quote Half Life? Unforseen Circumstances.
It seemed tier lists were subjective-kinda-factual lists by us, the customers, and testers based on reliability and how bad things went when it failed (explosions, flames, taking everything with it).
AXi were very very expensive. So they were top tier. As I say though they just weren't reliable . It does happen from time to time with PC gear.
And supposed quality, yes. I won't accuse Corsair of cutting corners by switching from Seasonic to some one else, but I guess they just got let down a bit. I *think* they actually make their own units now? no idea. It's usually fair to say that Seasonics are pretty bullet proof.
Most AXi units are Delta OEM as I remember. Given my choice, I'd take Delta over Seasonic-but remember my background in OEM and multi socket systems. I need a new one.