BenQ monitors are definitely worth price (based on other's reviews/opinions).
I've seen a picture to picture comparison between E2400HD and S2409W - S2409W wins by a small margin only. But if you can get S2409W for a cheaper price, then it is the way to go.
Like for ex: Phoenix at TE was selling S2409W at 12,750/- - It was a hot deal.
And no where S2409W is priced 24K, cause the dell representative itself has mentioned it under 20k (around 18k i guess).
Please let me know your budget mate. We can suggest accordingly