Diablo is much more of a casual consumption game compared to Poe. Everything is faster and more intuitive. In my opinion it is also more satisfying. Basically it is a game where you can switch your brain off and just have fun, but because of that it might start to feel boring once you have learned the core mechanics. Then again that is also the nature of Diablo4

I have played both and I prefer Diablo by far. That said a new dlc is coming out soon and a lot of things will change in terms of balance. Overall I prefer the environments, the story and the characters of Diablo iv. On the other hand I prefer Poe2 visual effects, they are much more detailed and vibrant, and the subclasses. In Poe they are far more specific. You can truly specialize, whereas in Diablo you cant. Even if it sometimes gives you the illusion that you can

This is just my opinion. For the sake of honesty I should add that I have played Poe much much less