this is a poll (o u o)

Depends heavily on what you want to put more emphasis on.
Ren'py is great if you think that visuals will help a lot in conveying what you want. However, it can be considered "boring" gameplay if you were to compare it to an RPGMaker or Unity game.
Unity and RPGMaker, on the other hand, can be fun and there's more room for exploration and freedom for both you as a programmer, and the player.
What I think:
If you're focusing more on the story and the flow of it, Ren'py would be ideal; however, if you're focusing more on exploration and allowing the players to roam around the areas, then either Unity or RPGMaker. All three are pretty good platforms to use, but again, it really depends on how you want to deliver (I personally believe Ren'py is more linear (with optional branching off) where the programmer has more control, whereas Unity and RPGMaker are more about the players' freedom and choice).
In terms of how easy it would be to make the game (getting all the resources + programming), all three are pretty much at the same level.