I thought it was pretty good, not the best superhero movie, but good. I went in with pretty low expectations, and they were exceeded. The characters looked good, though some were a bit underdeveloped, such as the main villians. The music was well done except for one scene where the music was just really different from the rest of the score (in a bad way). Finally, the writing was actually really well done. A few jokes didn't land well, but lots of plot points were pretty well done, though some could have been shortened or cut.
Overall, if give it a 7/10. It was a fun movie, but had a few "checking the watch" moments where it kind of dragged. Mera and Arthur were both fun and well done characters too.