A huge upgrade over Remake in every way: gameplay, music, pacing, characters, side quests. The open-world checklist aspects can definitely be the sort of thing that annoys people, but it isn't that bad honestly. It's fun getting to run around, earning points to exchange for some really awesome materia while getting exp and doing side quests related to some of those checklist tasks. It really is just fun.
Right off the bat, the game has an amazing opening that it follows through on as the chapters progress, but more importantly it coalesces into an indescribably incredible and simultaneously confusing final chapter. Everything up till then is understandable and falls in line with the progression of OG (along with Vincent and Yuffie being non-optional now which means they get some great interactions with the rest of the cast), but that final chapter is when the plot really becomes its own. And the final fight, the genuine gauntlet that is the final boss is superb, and it amazes they did it: it makes me wonder what they're gonna do for the final fight of the third remake.
And the ending. It's amazing, so melancholic yet you almost can't focus on your sadness cuz there's something even more pressing going on, something way more pressing than the OG's plot.
Overall this game definitely cements the remakes as amazing titles, and I just hope the finale manages to stick the landing. I believe OG is still better as of now because it's a complete plot and it doesn't have the very spoiler-heavy plot point going on, but I think that if the final game can stick the landing then this game series will be on par with the original and serve as an amazing follow-up to it. But time will tell on that, for right now, Rebirth is an incredibly solid game and has me excited.