I usually don't like rating games 5 out of 5 because that rating implies perfection, and because I usually either have at least one major complaint or the game just doesn't make enough of an impact for me to be able to give it that score.
This is quite possibly the first game I've ever felt confident in being able to rate 5/5. It's not perfect, but it's damn close, and it's definitely the best game RGG Studios has made.