Spoiler free impressions:
Just saw it last night too and yeah, it's one of the better modern DC movies imo. For reference, the only modern DCEU stuff that I've actually enjoyed are the Shazams, Harley Quinn, the 2nd Suicide Squad and the first Wonder Woman (which still had its issues). I think I'd put it on par with the Shazams in fun and sense of humor (maybe not quite as much "heart").
As Fero mentions, the plot is pretty straight forward to anyone familiar, but they did a good job with it. They clearly went "hold my beer" when it came to multi-versal plot points and there's some heavy duty fan service that, while entertaining didn't necessarily add much. That being said, I think the film earned it; it wasn't just there to try and gloss over poor story telling. The opening action set piece was absolutely ludicrous but paid off, and I did not feel the 2+ hour run time. One of my complaints about DC movies is the overreliance on unnecessary slo-mo. Obviously this would use a fair amount of it being a speedster flick, but it makes good use throughout. My only real critique at this point is the CGI still felt unfinished. Lots of soft faces and some points where one of the Barrys was so obviously a CGI doppelganger that he fell into the uncanny valley a bit. I think X-men's Quicksilver slo-mo is still the gold-standard for "speedster-vision", and I know it was super expensive to shoot, because they used tons of cameras and kept it as much practical as possible. With that as the bar, some of the sequences in the Flash become almost cartoon-like in appearance. I'll stop short of saying it hurt the movie, but it was distracting enough that I pretty much always noticed it. It's so consistently middling that I can't help but wonder if it was an intentional aesthetic choice.
Ultimately, there will be no way to separate the movie from Ezra Miller's behavior. I want them to get helped, but also be held accountable. I'm a little bummed that Keaton's Batman had to be attached to the behind the scenes issues, but he was great (as expected). Ultimately, the door is properly open for recasting regardless of what the director says and I still think it'd likely be the right choice. Miller is a talented actor, but can't be allowed to slide.