13/2 Indices, page-552

They all operate in the same way. The alternative would be trading Futures instead of Cash.
But in regard to patching the cash div adj hole, it would still make no difference as Futures and Cash ultimately move in synch during the cash gap-fill process. With futures, it just gives you a better feeling assuming they are not doing it.

The bottom line is the issue is not really about the provider, it's more about big boys wanting our dividend money. On the paper, it looks like a fair process. But yes, they usually come back to patch the hole and take back their dividend money -- sometimes instantly and other times after a while hidden within market fluctuations.