To my knowledge, the only difference between them is their quality. Getting a set in a normal dungeon (Blue Quality) and upgrading it up to Epic will make it the exact same as just receiving the same set piece from Vet in Purple quality.
The only place the difficulty has a difference in is in some Trials, and the Arenas, as they have some item sets with a 'Perfected' version that only drops in Vet mode for them, and come with just a tiny little extra stat effect on top of the normal effects. For dungeons though, no difference at all.
For upgrading when it comes to sets that drop on both difficulties, as in your post, no difference in dungeons, as stated above.
But for differences in loot pools, yes. Each dungeon has an end boss that drops a specific head piece, part of a 2-piece “monster set.” Those can’t be gotten on norm at all.
There is zero difference outside of it dropping as blue quality in normal and purple in vet. Only reasons for running vet dungeons are:
- You want an added challenge
- You're chasing veteran dungeon achievements
- You need the monster set helmet from the dungeon
Same things with random normal daily dungeons and random vets - there's no difference in reward which has always been puzzling.
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