This is probably the biggest 500 event in the tour. Half the top ten is there. I wonder if Paris Masters will have as much.
I reckon it is. Dubai has the second most prize money of the 500s and Barcelona has the biggest draw (56). But I think the main two factors are prize money and scheduling and Beijing has the best of both. Barcelona is wedged between Masters Series (meaning three weeks straight) while Washington is before two Masters (meaning three weeks straight also). Beijing is perfectly scheduled; an ideal warm up for Shanghai as it is in the same country and just the week before (two week straight is fine for most players, but not three).
I think Acapulco and Hamburg get the worst fields of the 500s because they don't lead into any Masters Series. Both are on clay and are have a hard court Masters a little while after them. They seem more for players who don't expect to do that well at the (hard court) Masters events.