I am not sure why there is such a buzz around this movie - in fact, one of the scathing reviews on IMDB manages to capture the movie in one word - insipid. The opening scene was annoying, with wooden dancing performance, and adding no value to the plot or other redeeming features. It doesn't really get better - and although Ryan Gosling and Emma Stone provide strong acting performances, their singing and dancing hardly light up the screen.
In fact, the movie is somewhat Bollywoodish as opposed to a musical - given than songs and dancing are a relatively small part of the movie - and perhaps they should have taken a leaf out of Bollywood and dubbed the singing! It's a movie about Hollywood, so, perhaps like Argo, that is the reason for all the rage. I found it uninspiring and mostly boring - I would recommend avoiding.