I assume this is this means the RAF Museum in Hendon? I went last month, there are some very rare aircraft there, including pretty much every British WWII aircraft you can think of (right to stuff like a Defiant!) a Ju-87, Ju-88 nightfighter, Me-109, Me-110... imho, versus Duxford, it wins except for the American collection, and of course the land warfare hall.
Martin