Yesterday, Kyon was helping prepare for an SOS Brigade Christmas party. But today, he wakes up to a whole other world. Haruhi and the SOS Brigade are gone, Koizumi's class is missing, Asahina doesn't recognize him, Nagato is still a Literary Club member and even Ryoko Asakura has returned. As the only person who notices that everything has changed, Kyon is left to discover what happened to his friends and figure out if his life truly is better without aliens, time travelers and ESPers.
Its premise and concept are very simalar and has alot of similar themes and basis. the whole kurisu going after okabe, and the very simalar kyon going after haruhi to change things back to how they used to be after something happens makes for a great show, and this is why thier so good and simalar
They both feature the protagonist trying to recover the other, which leads to a similar build in story. Also, if you enjoy the twist of the movie on the series, then you will like the other for the same reason. And, of course, they are both good on their own.
Involves the secondary protagonist chasing after the main. Both involve them trying to recover the other through sheer clues and help from other acquaintences. However, the Haruhi movie was a bit more well-done than Steins since the original for Steins was Top-Notch. I guarantee the enjoyment of these two productions.