Mission: Space is not Horizons. For this reason alone, I don’t think it will ever get a fair shake among serious Disney fans. To be sure, I’m not saying that Mission: Space is superior to Horizons. While I have incredibly vivid memories of Journey into Imagination, World of Motion, Body Wars, and other EPCOT Center attractions, I don’t really recall Horizons (likely because my parents didn’t care for it, so we didn’t go on it much when I was a kid). Given my normal preferences, I think it’s safe to assume that I’d prefer the long, story-driven Horizons over Mission: Space, but I still enjoy Mission: Space. Unlike a lot of classic attractions that have been replaced by abominations (I’m looking at you, Journey into Imagiantion), Horizons was replaced by a pretty decent attraction in Mission: Space. Some people will never acknowledge this, though.
While Mission: Space might have cost too much, might not be as ambitious as early plans for a space pavilion, and might already be dated from a tech-perspective, it’s still a pretty good attraction, overall. I think the architecture of the building is really impressive, and it’s certainly fun to photograph. I enjoy the queue a lot, and its details there make the experience really immersive. Similarly, I think the music adds a lot to the experience.
But, at the end of the day, it’s still not Horizons…and that’s all that matters for some.