Originally posted by Maxime Ferlatte
The main advantage of 1.C4 is that most people don't have a whole lot of experience against it and don't have anything special prepared to meet it.
Let me just add that Black doesn't even necessarily HAVE to know anything in particular to play against the English. A King's Indian Defense player stays with his basic setup, a Dutch player gets his e5-f5 pawn duo without a fight, a persistent QGD or Slav player knows he can play e6 and d5 or c6 and d5 and practically force a transposition of some sort, a Queen's Indian, Benoni, or Nimzo player can practically stumble into a reasonable Hedgehog setup, and the Neo-Gruenfeld is pretty much what happens when a Gruenfeld player is persistent in his approach when facing 1. c4.
And it gets worse. I played the English in an OTB tournament for the first time two weeks ago after studying the English on and off for twenty years (I'm a long time KIA player, and I study all white fianchetto openings for a better perspective). I was using IM Craig Pritchett's "Play the English" as my approach, and both black players I faced transposed to the Accelerated Dragon on move five. I looked the games up in Pritchett's book, and for the line in question he has in a note on p. 114 that "It is also very important to be aware that his [black's] main alternative, 5. ... g6, transposes after 6. e4 to the Maroczy Bind Variation of the Accelerated Dragon, which unfortunately must lie outside our coverage."
The English has so many lines and transpositional possibilities that it is almost impossible for an amateur to be "booked up". Fortunately, understanding themes and ideas can go a long way at our level in the English, but I think "mastery" only comes to the players who already have "master" as a title in some form.
This is probably a semantic issue, in that an amateur Sicilian player can practically play 1. c4 as their Sicilian variation reversed, treating all non-...d5 lines as forms of the Closed Sicilian reversed ( ...e5/...f5 lines as a Grand Prix reversed, lines with ...c6 as an Alapin reversed, black fianchetto lines as a pure Closed reversed, lines with ...Bb4 as a Moscow/Rossolimo reversed, etc).
It's just the "easy to master" part that some of us would consider inexact language.