I would like to say that EVs are better from a competitive standpoint, and for the most part they definitely are. Learning how to specifically optimize EVs for certain Pokémon to account for certain matchups adds a layer of complexity to battles that doesn’t necessarily “break” the game in the same way that other additions to the games have. The opportunity cost that comes with EV optimization helps balance Pokémon out, whereas with stat experience this often just helped make the rich richer and gave the metagame a lot more emphasis on bulk and defensive play.
From a casual perspective, I do still think stat experience has some merits over the EV system, though. That’s why it’s hard for me to say one is better than the other even if EVs are inherently a more variable system. Stat experience feels like the kind of thing that’s easier to understand for newcomers and is an overall upgrade over EVs for the majority of the single player experience, save for battle facilities and the like. I’ve also had situations pop up in certain games where because of the Pokémon you battle against, that creates a disparity in the EVs you’ll be getting during the main story. Unova is especially bad about this, with Audino farming indirectly granting more HP EVs but the real issue is how deceptively few Pokémon in Black & White 1 give Special Attack EVs. Outside of the Celestial Tower, I can only think of a handful off the top of my head that actually do, and that’s not really that big of a deal but it bothers me when physical Attack EVs are much, much more readily available, which may have something to do with why most Black & White 1 playthrough teams consist almost entirely of physical attackers. Alola is another region where this happens but to a much smaller extent, with most of the fully evolved Pokémon being unusually slow resulting in less Speed EVs during the late-game than usual.
The issues with wild Pokémon and trainers’ Pokémon generally isn’t that big of a deal at the end of the day when well-designed level curves are much more important to single player than EVs will ever be, but to some extent stat experience does help to balance out the poor level curves of some games. Johto particularly comes to mind, as the large majority of Pokémon in GSC you’ll be battling don’t have any stat experience at all and by the time you reach Clair you’ll likely have enough of it to where the level curve is… still bad, I‘ll admit, but not as bad as it could be. I would estimate that if your team is in the low 30s when you reach Clair’s Gym, stat experience would make it so it feels more like the mid-30s instead. Not a huge difference, but it’s something.
Overall, I do believe EVs to be the better system but I voted for stat experience in an effort to highlight the marginal advantages the system does have over its successor. Not to mention, sometimes EV optimization can backfire if your opponent in, say, a tournament bracket knows what your stats are looking like and is allowed to change their EVs before your next Best-of-3. Imagine thinking you lost a Speed tie only to later find out your opponent outsped you by a single point so it effectively changed nothing about the outcome. That would be annoying to me personally, especially since there’s nothing I could have done about that in older games where speed ties are handled a bit differently. But that’s for another thread, I’m still doing research on recent findings.
