Just got back from the Australian premiere and I loved it! There was such a great sense of community at the screening; it was a 1,000 seat event cinema and they had a full house. Everyone was applauding the fan favourites as they appeared, gasping for the big clashes and laughing at the character interactions. Maybe I'm still too stuck in the idea of One Piece being (in the English speaking world only) the underdog of the shonen heavy hitters due to the bad first impression the 4kids dub made, but I wasn't expecting such a big and enthusiastic turnout. Glad to see we've come so far!
I'm sure some people will strongly disagree, but I think Stampede was exactly the right way to do a One Piece movie. The adventure arcs in One Piece work because they aren't standalone things. The core stories of most canon arcs are formulaic, but they work because of the underlying lore and the way they introduce characters and concepts to the wider OP universe. Movies, which are inherently non-canon and disconnected from the main plot can't possibly emulate that, so they end up feeling flat next to their canon counterparts (not to mention the issue of Oda's storytelling being to wide in scope to fit in a movie's runtime). Stampede sidesteps this by being all action and all fanservice start to finish. It's great. Conversations and battles we can only dream of in canon came to life, characters I would never have in a million years guessed would escape the background of a movie had actual (though brief) speaking roles, and the team-up nature of the main fight with Bullet has me more convinced than ever that the end of Wano will be a co-op fight.
The movie also did a great job of capturing the chaotic energy of the manga. Oda draws a very motion-heavy kind of comic and often has multiple areas of action in a single panel, which gives the impression of lots of things happening at once despite the series' slow pace. The no-brakes action and constant need to scan the crowd shots for familiar faces and referential details was the closest the anime has ever come to properly replicating this (though Gold was a good effort). I can't wait for the blu ray to be out and see exactly how many characters people are able to find with the ability to freeze frame.
Spoilers about a certain romanisation below. Not sure if it's still meant to be under wraps here since I haven't checked into this part of the board for a while.
! I think we're the first English-speaking nation to get it, so people might be interested to hear that the subtitles did say Laugh Tale every time that particular name came up. That's not to say that it's official, I'm pretty sure they have local people working on releases such as this, since it was distributed via Madman rather than Funimation, but it may be an indication of whether or not we'll see a broader retcon.
Also on the topic of translation, they went with Clank Clank Fruit for Douglas's powers. Not certain if that one has come up already.
So yeah, tldr: saw it, loved it, want more