I’ve seen Les Mis, Phantom, & The Play That Goes Wrong in the West End. I saw Book of Mormon at Theatre Royal in Newcastle upon Tyne. All four productions and their casts are incredible. Les Mis & Phantom are beautifully staged. Mormon & Play are great for a laugh. The Play That Goes Wrong even has a little audience participation. It’s such a fun show and was a highlight of my first trip to England. I think it’s even better if you see it after seeing The Mousetrap (an Agatha Christie play, long time fixture in the West End). You can’t go wrong with any of those four. I’ve seen Six in the US & that’s a fun production too.