Of the two, Halo is the weaker show. I can see why fans of the game are so upset about how much liberty the writers took with the source material. That said, I still found it to be an interesting story with characters that I came to genuinely like: especially the Spartans and Cortana. I am interested in seeing season two, if only to see how the stories built in season one develop ... oh, and for the characters to actually see a Halo in something other than a dream-walking sequence.
Stranger Things is still one of the best shows out there even if there were parts of this season which made it my least favorite season so far. In particular, I did not like this season's portrayal of the military, churches, and drug use. I was also disappointed that the parents are still largely caricatures even though there had been strides made with Karen (Nancy and Mike's mother) in season three with her pep talk to Nancy. Still, despite my issues with several elements of this season, it also had one of the most powerful moments that this series (and maybe any series) has ever had. In short, there is good reason why so many people are suddenly interested in Kate Bush's song "Running Up That Hill." I was in literal tears.
Unfortunately, we have to wait a while to see what happens as Halo's second season will not be out until next year, and the fifth (and final) season of Stranger Things might not debut until 2024.