Sure Yahoo provides delayed data (15mn I think), but hey this is free, not throttled, reliable and very fast. If you just want to get the option chain for x symbols without the quotes every morning and store it, it's definitely a good deal.With parallel tasking, you could get several hundreds option chains within a second.
?
Clean: well organised response, without redundancy, such as: Exchange - Trading Class - expiry - array of (strike - right (Put/Call) - ConId)
Valid: EXHAUSTIVE listing of VALID combinations (expiry/strike)
Francois G