Short answer: yes it's better than sora yori.
Although it's really difficult to compare Sora yori and gridman since they are both such different shows, I truly believe that Gridman will end up being the better show. I really enjoyed Sora yori and it definitely was one of the best shows of 2018, but I felt like it definitely got oversold to me by a few of my friends. I think if I just naturally picked it up and followed along I would have gotten a lot more enjoyment out of the show because there's nothing better than a show exceeding your expectations. I love SnB Genesis a lot more because of how much it exceeded my expectations for it, but it's extremely difficult to meet expectations when everyone you talked with hyped it up so much.
It was an extremely solid anime melodrama and it even managed to not have a love story as a b plot which is an absolute rarity in the world of televised anime. The script was super lean and the pacing was superb. All of the girls got to have nice arcs and everything that was brought up plot wise was dealt with in a natural and fluid way. It feels like absolutely forever since there has been a quality anime melodrama made as well as Sora yori.
Even though animation style was slightly different from the norm, however I think my biggest problems with Sora Yori was the fact that visually Madhouse took 0 chances visually on the show. That's why I love Gridman so damn much. The story is great and the direction is superb. Amemiya is flexing his damn muscles with his first big directing gig. From what I understand Amemiya even storyboarded the best episode of Gridman to date, the 9th one, and his visual style is amazing and made the emotional impact of the latest episode even greater. As a whole the shots in Gridman are absolutely gorgeous. It feels like Amemiya has really thought out why things are drawn the way they are and that each scene is visually designed as a way to aid the story. The damn bus scenes in Gridman evoke the train scenes from Eva. In fact, I feel like Gridman is the best portrayal of loneliness since Eva. Overall I have high hopes for Gridman and with just a handful of episodes left I have faith that things will continue in the same direction.