I used to like the old Dunlop cement which - to me - seemed to stay 'tackier' longer than Clement etc. However - and this is a true tale - once upon a time a top UK continental based pro visited our then LBS and brought with him a top continental pro and ex-TDF winner who was riding the Vaux GP next day and who wanted some rim cement. Without thinking LBS owner gave him a tin of Dunlop which the continental pro virtually threw back at him saying 'What is this??!! I want Clement!!' British pro then explained that Dunlop was not liked on the continent because it melted under the heat of braking on long descents whereas Clement didn't. Luckily LBS also stocked Clement so continental pro went on his way a happy little man.
Today is the yesterday of tomorrow.