Data dominated this year's upfront presentations, as each network claimed it had the best data platform to help advertisers and media buyers enhance TV buys. Now that upfront business has finally wrapped, we asked several buyers to anonymously review the networks' individual data offerings and separate the contenders from the pretenders. Their conclusions:

It's a three-horse race. To buyers, three players stand out: NBCUniversal, Viacom and Turner. They gave low marks to ABC, CBS, Discovery and A&E for supplying little more than the data they and their clients already have access to. Said one buyer: "All ABC is doing is optimizing your prime-time inventory, which you could do on your own."

Optimization less than optimal. One buyer praised Viacom's willingness to optimize its data every two weeks, though another said NBCU's quarterly optimization was just fine. "On our side, it requires man hours to be changing the schedules all the time as well. I doubt most clients would need to do it more frequently," the buyer said. Turner isn't allowing any optimization at all, "which obviously presents problems because if audiences are changing their viewership habits, you want to be able to follow them."

They're down with ATP. Buyers gravitated toward NBCU's Audience Targeting Platform because of its ability to provide them with data from Comcast set-top boxes. "That's very appealing because that has not been offered in any platform to date," said a buyer.

They're going with what they—or their clients—know. "I'm honestly leaning more toward NBCU because we do a lot of business with them," admitted one buyer. Another agreed that familiarity goes a long way, especially with platforms they've already beta-tested: "If I had to go to bat for one of them to a client, it would probably be Turner. Because I've already used it, and that holds a lot of water in terms of executing these kinds of things."

Bigger is better. Buyers like that NBCU and Viacom products "span a large swath of different networks and different inventory. The bigger the available pull of inventory, the better targeted you can be," said one. That's where Turner has a tougher time measuring up. "If you're cutting the data a little thinner, then you start to run into sample-size issues and viability of buying against certain more granular targets," said another buyer.

Data delay dilemma. Despite advances made by Viacom, NBCUniversal and Turner, buyers agreed that most of the talk about data during this year's upfronts was just that. When it comes to data, explained one buyer, "the upfronts was mostly, 'Do any clients want to do this?' 'Client X does, OK.' 'Give us $3 million more.' 'Boom, let's write that down on a piece of paper.' Then they're going to do the data tests and we'll figure it out later."

In the end, the platforms are "a lot more complicated than a lot of people realize in practice," said one buyer, who spent six months working with a network to determine how to run just 10 percent of one advertiser's buy through its platform. The buyer added, "I think that's what a lot of people started to find out this year."

This story first appeared in the Aug. 17 issue of Adweek magazine. Click here to subscribe.