Might as well answer this since I have experienced both haha. I did not like either but a lot had to do with the amount they cost for the performance you get. The celestee to me sounded thin, flat and lacking bass. I wasn’t even sure what kind of music would sound good on it to make it worth its msrp. The radiance I got was boomy but the bass had like no texture or definition to it and the vocals sound plain wrong (even my coworker who knows nothing about headphones picked this out without me mentioning my opinions). However it was so comfy and if it was MUCH cheaper I would definitely have kept it.
However, I recently talked to resolve from the headphone show about my issue with them and apparently they have a fucked up pad variance that can mess up the bass drastically.
So ya…
The only advantage the radiance has over the aeons is their portability. I’ve never tried the akg headphones but it’s really price for performance that’s disappointing. Like these are a $1000+ headphone (considering Canadian dollars). For that kind of money you could buy a practically endgame iem that is absolutely fucking Fantastic in every way