I've watched S1 but haven't watched S2 yet, I've downloaded it ready for bingeing. The idea of a musical episode puts me off to be frank. Pretty much every show that has had a musical episode has made itself look ridiculous and I am afraid this will do the same. The only show I can think of that has pulled it off is the Flash where Barry Allen realised immediately he was trapped in some kind of illusion and flatly refused to sing a note. (Grant Gustin actually has quite a good voice)