Rant spoiler-ed below, because its mostly just complaining, but it feels like a lot of games lately have added 'gamified xp' to their systems, and I don't understand the appeal at all. The most positive any player I've talked to has felt about the systems are 'meh, I could take it or leave it', with most slightly disliking them.
So, mostly, I'm looking for people that like these kinds of mechanics (I have to assume they're out there if so many games feel like they're adding them), and what you is it you like about them.
But I feel like Milestone XP just makes the most sense for any traditional coop party RPG.
rant
I like trying out a bunch of different systems, and there's a lot to like, especially with a lot of the smaller games out there. I do like there 'narrative' approach ttrpgs feel like they've been taking recently, but between Chronicles of Darkness, ICON, Forged in the Dark, Apocalypse world, etc., and all there spinoff systems all having XP be earned for specific actions in game, its just a pain in the ass, that takes me out of the action.
I mostly GM, but I strongly prefer milestone XP. For some of the above games, its easy enough to gut their bespoke XP systems out of it, and just have players advance over time, but in several of them, it fucks with the overall balance, since several actions are 'bad', but made worthwhile because they earn XP.
But I don't like the feeling of interrupting game to award point, and adjudicate character advancement. And I hate systems that have players advance unevenly. There's always going to be a certain degree on uneven-ness in player attention, of rules mastery, and of spotlighting. As GM, its important to manage those so that everyone gets a chance to shine. But it just feels like increasing that workload for the GM, to need to additionally pay attention to the XP, and try to drag or XP share the players that don't find those systems engaging to not mechanically fall behind.
And as a player, I tend to have higher system mastery and attention than the others I play with, and tbh it feels bad to end up with more XP because of that. But also, it feels bad to knowingly pass up free XP by purposefully not engaging with those systems.
Really, only Call of Cthulhu and Paranoia feel like their gamified XP fits, and that's largely because the games are supposed to feel hopeless and unfair, and in the case of Paranoia, gamified and playing favorites.
As both a DM and player I get very different experiences from gamified and milestone XP, and they both have their place in different settings.
Milestone, for starters, is much easier to deal with. No tracking, no checking everyone's getting equal opportunities, no throwing in filler to knock the XP bar up a bit. It lets you keep to the important story stuff, concentrating on the main narrative, and ensure an appropriate power level as you progress.
Gamified XP on the other hand, when properly implemented, encourages exploration and interaction in a less story-bound structure. There's an active incentive to look for side stories and random issues to resolve instead of heading directly for the objective.
To use 2 pathfinder adventures as examples, I used milestone for Rise of the Runelords and am using gamified for Abomination Vaults.
RotR is a classic fantasy adventure to defeat a returning evil, that takes players from a small village to a large city then out into the mountains following the plot threads. It's a very linear adventure, with some side activities during periods of downtime, but mainly concentrating on progressing through the country and story to find the BBEG's lair. I started using the regular xp system and then switched to milestone after I realised the players were about a level and a half behind where the AP wanted them, and would get stomped by the next boss fight. Milestone worked much better, and let me cut boring bits and expand others without worrying about the XP cost. AV is instead based around a mega dungeon and the town above it, with lots of side stories that link the contents of the dungeon to the town above it, if you spend time actually interacting with the town instead of using it as a place to rest and restock. Even I, with my love of tactical combat games, would get bored if that's all it was, so gamifying the XP encourages the players to spend their time outside of the dungeon roleplaying with the town itself. It also gives me opportunities to share the story(/stories) of the dungeon in a way that makes sense, instead of forcing lore dumps in between combats. It also frees the players from the need to explore every inch of the dungeon looking for fights, as they can easily make up XP through roleplaying.
Choosing which to use is a matter of matching them to the way you're telling the story and how you want the players to interact with the world, rather than one being better than the other, just like with choosing what system to use.
Okay, I get that.
I still feel like my preference is for roleplay to reward in-universe rewards, and character advancement to be milestone. For a similar example, with my running Strength of Thousands PF2e game, I added in extra opportunities to have the different NPCs help the PC, in a way outside the fairly gamified rewards pre-written into the book. But, to a certain extent, that is more work than just dumping XP on them.
I do dislike the PF2e AP as-written, 'give extra XP for fully digging into conversations' thing that crops up in some social encounters, as that's another thing where, like, that info is useful in and of itself. I don't think players need rewarded for getting information that is of material use to them. But, I've been doing it milestone anyway, so its a moot point for me on that front.