HALF the price is a strong argument for the EPIC 🙂
I've been on the EPIC in 2021 and I have mixed feelings about this ship. It depends if the "ocean feeling" while cruising is important to you.
The Epic is very much built with an inside focus. There is no walk-around promenade deck. No front views like the Spinnaker Lounges on other ships. Everything in the public spaces inside is very dark and you barely get to see daylight or the ocean when inside. This is what I disliked most. So if these things are important to you and the price thing works out, then the other ship might be better.
See my review on the Epic here:
https://boards.cruisecritic.com/topic/2799317-worst-norwegian-ship/?do=findComment&comment=61942741