All reviews are very positive. The paper improves over [BMSW] in a very interesting way, and forms an interesting interplay/complimentarity with [BMSW]. In particular, it presents a clear and tight characterization of what the learner's no-regret property implies for the opponent's best behavior. [BMSW] Mark Braverman, Jieming Mao, Jon Schneider, and Matt Weinberg. Selling to a no-regret buyer. EC'18.