Which do you prefer? I’ve been using milestones in my campaign, but can see why XP could be cool to use.
1 point
Milestones, because it reduces fiddly tracking of XP during the game and makes it easier to plan ahead on boss encounter difficulty. Plus it allows for a convenient time to level up while basking in the glory of their success!
Plus it doesn’t encourage players to be XP seeking in their actions so they can play their character how they see their character.