Obviously, via my title for this post, they have probably one of the most extensive audience targeting otions in their platform. If you can't find an audience to target within their platform, they probably don't exist. They also have amazing account and trader people that are there to answer and help you navigate any problems you may be having for the platform as well as tips to use it most efficiently.
Contextual site targeting an the Long Tail - it literally hides 50% of you actual conversions so it's impossible to tell what sites are converting most efficiently. Yes, there is a separate conversion report which gives you a ton of insightful data, but you have to pull it separately and it does not also provide the costs to go along with the media that converts, so the long tail insights that you may or may not want to add to a site list based on performance, are impossible to tell. Also, for contextual targeting, there are so many stronger DSP's, some without any minimums, that give you a much better comprehensive idea about what site's are in a given category, URL and even full URL and what their average CPM clears for and the SSP's that each site sells against. They developed this "predictive clearing" price "selling feature" as more and more sites are going to 1st price exchanges, which is great - but relying on a DSP to know the pricing for inventory just what a trader can know and optimize for given their dependence on "bid factoring" vs. CPM price adjustment - sets traders at a clear disadvantage with being knowledeable and most efficient in their tradings vs. giving the DSP more profit for theiir terms vs. a brands needs and CPA strategy. Also, the new megagon format is absolutely a backwards trend and counter intuitive to helping traders be more efficient in their work flow and targeting ability. Before Megagon, you could easily skim over an ad group's settings "without the process of downloading an excel sheet) to ensure everything was in check. Now with Megagon, you are no longer able to have a contextual ad group targeting both categories and top sites within a paticular industry and have to separate them ve. general category vs. keyword categories, vs. site lists...which I imagine is a cost saving nature for them, as most DSP's researched we've discovered you need to create separate groups for these things - but it now no longer separate them from the pack.
We provide a complete managed service solution for agencies out there that don't want to get into the weeds and prefer focusing on the bigger topline strategies. The Trade Desk provides a great platform and a great topline user interface (for pacing, budget management) and extensive access to data targeting along with their high QPS rate which increases the odds of winning a greater percentage of inventory for our clients.