S.No. Real Time Bidding Header Bidding
1. Daisy-chaining auction in waterfall structure doesn’t allow potential bidders to bid for premium inventories as advertisers bid as per their position on the waterfall chain. Unified auction allows the demand sources to bid for each impression at the same time. Advertisers can bid even for premium inventory.
2. Direct deals are given top priority in terms of ad serving. The winning bid in the auction process goes to publisher’s ad server where it competes against direct sold ads and highest bid serves the ad.
3. Following the waterfall model, each time the inventory gets rejected and the publishers lowers it price and place it for auction process. Due to this, they fail to get the best price.


Simultaneous bidding lets multiple ad exchanges and ad networks participate in the bidding process. These results in more competition among the bidders and publishers fetch best prices for their inventory.
4. No transparency in bidding process, publishers only gets to know the highest bid. Publishers can see all the bids and not just the winning one. He can also know the details of who the winning party is.
5. Google DFP gets priority over other platforms. Uses open source infrastructure like Pre-Bid which is not biased for any platform.