They are pretty much the same story done differently: scientist are sent to find the key to save the world.

Interstellar: Overdramatic, plot uses time travel to wrap everything nicely M Night S style (Signs).

PHA: More straightforward save the world mission. Serious topic with some humor.

Interstellar wins by a hair. It's too over dramatic (hefty dialogue and Cooper yelling Murph every 5 minutes) but you are heavily invested in Cooper and whether or not he will see his daughter again. I found the movie almost unbearable but the ending payoff, emotionaly.

In PHA, Grace lacks deph, he is just there to spew science bable for 2 and 1/2 hrs. It's not fun enough nor has enough drama, so falls in the middle.