I find that if you choose not to transpose to a d4 opening, that English games tend to follow long-term strategic plans better than most other openings. If you favor that sort of a contest over an early tactical melee, I think c4 suits.
On the other hand, if you DO like to use it as a transpositional weapon, opening with say 1.c4 2.Nc3, then it allows you to play the more aggressive d4 openings, without forcing you to deal with the Nimzo.
So after 1.c4 e6, 2.Nc3 d5, you can push d4, and still get a favorable QGD exchange. Whereas after 1.c4 e6, 2.Nc3 Nf6, you can keep it in independent waters if you choose.
Why do you play the english opening (1. c4) instead of 1. d4 or 1. Nf3?