First, some thought:
You cant compare Eevee with Redshift, Eevee has screen space reflection, thats why its so fast, is not a raytracing render engine like Arnold or Redshift is. I dont think it can reflect caustics (maybe im wrong), but im pretty sure it cant refract several objects behind each other. You can however compare Eevee with Redshift RT, the upcoming real time solution, but thats a dicussion for another time.
Its good enough for everyday work and some more (thats why im adopting Eevee into my workflow as well), but lets get realistic, shall we?
Now, on the other hand… Prorender was painfully slow and thats why I bought Cycles 4D a couple of years ago, and then Redshift for my work. I can understand Maxon decision to buy Prorender - Mac users- though I cant understand Maxon decision to sell Redshift to its users. I wish C4D just discarded Prorender and gave Redshift for free to its user base, but, hey if someone is happy with ProRender, good for them.
Anyway… lets get back to the topic… denoisers, every major render engine has one, and they all have something in common… you cant use low samples and expect the denoiser to magically enhance the scene.
Final thought, Maxon owns Redshift, but I dont think they own Prorender, im not sure if they develop Prorender. Maybe im wrong?