Quote from iqfeed:
What you are seeing is aggregation at the exchange. The exchange has 3 different feeds currently, and depending upon which feed the vendor/broker is on you may see different levels of aggregation. We are currently on the ITC feed from the exchange. We are in the process of moving to their Fix/Fast feed which we are told has little or no aggregation at the exchange. I can assure you DTN sends every trade we get from the exchange.
Interesting I didn't know there were 3 feeds, although I suspect that most traders would not.

And from this source, I was told that Esignal uses RLC feed from CME. So I guess IQFeed is the only one so far that is using an aggregated data source. Good thing thus far is that IQFeed is hardly down in a fast market, it gets lag but not down. (Transact data was never down from my past experience).