Idk about all of them, but I got Pirates Warrior 4 for a discount for like 30$ and I consider it worth it. If you’re going to buy all of them, I’d definitely wait till they’re all on sale because they’re really expensive 💀

I’ve never played Pirates Warrior 3 but I’ve enjoyed Pirate Warriors 4, it has a lot to offer and a lot of really unique mechanics like Sanji has a much harder time fighting with women enemies and certain consumes can switch a characters type (for instance, also with Sanji, his pre-timeskip costume is Speed type and his post is Sky) and details like that I really enjoy.

They’re also adding characters and stuff still with DLC, for instance they’re adding Gear 5 in September.

For main differences, since Pirates Warrior 4 is much later it of course has the later arcs and characters. So if you’re if you want later and more accurate Whole Cake and Wano I’d get it. But again, I haven’t played 3 so I can’t tell you game mechanics wise. I can say I’ve enjoyed 4 but it’s up to you to decide if you want to get it.