It's hard to really explain. It got such a following because it's such a bizarre concept (a hip-hop musical about the founding of America), and it's so cleverly written, and unlike anything else that's out there. It's one of those shows that you'll either get caught up in from the opening few lines, or just sit there and think "people like this?"
It's such an energetic show, too. There's so little scenery but the choreography is tremendous.
I can tell from this thread that it's highly rated, I don't know much about it.
Can anyone sum up why it is so good?
That's an awfully big question. Suffice it to say that Miranda is a bloody fantastic lyricist, and the soundtrack stands up entirely on its own, constructing a clear narrative without the need for visuals. Basically every track is a belter in its own right, with heavy inspiration from the greats of Hip-hop and Rap, as well as a few direct references peppered throughout.
The choreography and set design- which are frequently the same thing, with dancers moving around and often becoming furniture- is just the icing on the cake.
I'm just under halfway through the Cumberbatch version of Hamlet (Rosencrantz and Guildenstern have just turned up), and I'm loving it so far.
I can't quite get over the fact that Polonius is played by Bishop "don't call me Len, you little prick" Brennan from Father Ted, though
"My liege, and madam, to expostulate what majesty should be, what duty is. Why day is day, night night, and time is time, were nothing but to waste night, day, and time; Therefore, since brevity is the soul of wit, and tediousness the limbs and outward flourishes, I will be brief.