I love this movie.
Eva 3+1 and the whole rebuild series is complimentary to the original series. If you're going into this movie hoping to find if it's a parallel universe to the original series, or if it's a time loop, crazy mech action, a romance drama, or anything of that nature, you'll be approaching this series in a way that will leave you dissatisfied.
This is a psychological/meta commentary. It's experimental, it revels in its babel and self-indulgence, and that's what I love about it. It examines itself, it's exploring themes around the series, fans of the series, the creator, and what the series means to all of the above.
The rebuild series takes the messages and ideas of the original series and takes a step forward, and this final movie is where that is cemented.
If you liked the last two episodes of NGA and could appreciate what they were trying to do, then there might be something here for you.