XEO, which I only found recently, is the exact same as the OEX, except it is traded a bit less by pit traders, and it is european style exercise, thus, the options cannot be exercised prior to options expiry...
thus, if i am short calls, as I am, and the go ITM, I don't have to worry about getting assigned, unless it's OE Friday.
That, and, I don't like being taken advantage of by the boys in the CBOE pit. I've been there. I've seen it. They eat 10-lots for breakfast...