Finally saw GOTG3 tonight. I'll admit I found the first 2/3 of the movie to be a bit aimless and the jokes didn't land as much as I would have liked. When the movie in general is as dark as this one, if the jokes aren't landing, it can at times feel like a bit of a slog, which it did. It also didn't help that this movie was needlessly about 20 minutes too long in my mind, which added to the aimlessness. With that said, now that I've got the negatives out of the way, I found the last third of the movie to be fantastic, funny, and exactly what I wanted from this movie all along. What made the ending so good was how fitting it was for a conclusion to the trilogy. I feel satisfied. Saw the movie in 3D, and while I would say it only marginally enhanced this movie for the majority of the movie, the third act ensemble fight scene was maybe as good of a 3D fight sequence as I've seen, with all the unique camera angles and rotations. It made that scene twice as fun as it already was.
With all that said, that third act was good enough to make this movie as a whole a positive good movie for me, but not top-tier MCU and not the best Guardians movie either. That title is still reserved for the first one. The second Guardians movie is also probably consistently better than this one, but the highs of this movie far exceed anything in the second one. The net effect of those two movies probably puts them on somewhat equal footing.
Anyway, those are my thoughts. The movie was generally a lot darker, scarier, sadder and less funny than I would have guessed. Not all of that is bad. I maybe made the mistake of taking both my 6 and 9 year old daughters to this one with me, and while they both love the other Guardians movie, I could tell this was a bit much for them. They still had fun, but I'm pretty sure they were generally terrified for a lot of the movie, which made it last in their Guardians movie rankings.