Henri de Lubac was not only a great Patristics theologian, but he also specialized in inter-faith dialog, especially that of Buddhism. He taught extensively on this topic while in Lyon and authored books on it as well. I know of at least one such book, which was translated and published into English in 1954, Aspects of Buddhism. This work had both a Nihil Obstat & Imprimatur. I acquired a copy of it through Loomes!
Hans Urs von Balthasar regarded the dialogue with Buddhism as having a "greater long-term significance for Christianity even than the ancient dialogue with Greek thought, which decisively shaped the history of Christendom." Raymond Gawronski, S.J. authored a great book on Balthasar and the Spiritual Encounter between East West entitled Word and Silence, which was published by Eerdmans in 1995.
Fr. Luigi Giussani also had a interest in Buddhism and maintained close friendships with many Buddhists as recorded in this TRACES article, Buddhism - Habukawa and Fr. Giussani.
I would also refer everyone to Pope John Paul II's chapter of Buddha, which is short, but the best critique of Buddhism that I have ever read.
Thomas Merton has been criticized because of his study and writings of Buddhism, but as you will see both above and below, he was in a fine tradition of great thinkers doing the same, including many monastics.
Merton and Buddhism - past event, but this document lists some great resources
Merton and Buddhism: Wisdom, Emptiness & Everyday Mind - audio of the entire conference directly above
Towards a Critical Appreciation of Thomas Merton
Thomas Merton Revisited
Various articles on Buddhism by Joseph S. O'Leary
Towards a Buddhist Interpretation of Christian Truth
Emptiness and Compassion
Conventions and Ultimacy in Japanese Religion
Buddhist Serenity in a Time of Rage
The Society for Buddhist-Christian Studies