It's a good place to get solid data but it's quite expensive. EOD history for SPX alone is $250 apparently. All symbols are $2500 and my understanding is that this is just CBOE options? Is CME not in there?
iVolatility told me it would be ~$1000 for EOD chains + IV & Greeks since 1990 - just for SPX. CBOE is partners with iVolatility so I imagine their data is decent, but I can't bring myself to drop that much on it for a simple personal project.
Since CBOE is the exchange itself, I'd assume the quality of the data is at least the same as iVolatility, if not better.