I remember reading about some famous 18th century German critic who said, "I would gladly give 10 years of my life to extend Sterne's by one," or something. True or not, that's the kind of obsessive devotion Tristram Shandy engenders.
To me, Sterne is the only person who can be mentioned in the same breath as Shakespeare in a "greatest user of English" debate, if there ever is such a thing.