Roguelikes are even different: Dungeon Crawl Stone Soup is known to be hard to win but easy to play. It has tutorials and a hint system. They're aiming for zero need to read online guides. Compare that to Nethack, which is chock-full of weird stuff that you have no hope of discovering on your own.
Having won both I think that the only real difference is DCSS takes such a ridiculous amount of time for a 15-rune win that you just don't care by the end. I felt like I had to go through the same amount of spoiler reading, overall. And both are easy once you have a solid build strategy.
Have you played Brogue? That is really something special. It's a really stripped down game inspired by the original Rogue. There are no classes, so your build depends on the items you find. Rather than experience points, you'll find a finite number of scrolls of enchantment to spend on items. The tight food supply forces you to descend, which in turn prevents you from saving scrolls of enchantment for too long because you'll need to spend them on your items to survive. But the longer you can delay the better, because if possible you want to spend them on top-tier items.
