The Doubleclick interface is easy and simple to get a hang of. The options are slightly limited compared to other DSPs. But, for a simple campaign, this is a great DSP to move forward with. They have a ton of data and can plug into a lot of different partners.
What is Google Marketing Platform (formerly DoubleClick)?
Google Marketing Platform (a combination of former DoubleClick advertiser tools and Google Analytics 360 Suite) is a set of tools for marketers to manage their advertising campaigns. DoubleClick was acquired by Google in 2008. It focuses on uploading ads and reporting their performance and also provides forecasting tools to help predict future campaign needs. Bid optimization tools help manage pay-per-click (PPC) campaigns across search engines (e.g. Bing, Google, Yahoo!).