Most of what we know about Marcion comes from what the early Church Fathers wrote against him. The first mention of Marcion was in Apologia by Justin Martyr, a contemporary of Marcion. A century later Polycarp's pupil Irenaeus describes a confrontation with Marcion in Adversus Haereses which was taken further by the choleric Tertullian in Adversus Marcionem.
The most important outcomes are that we know that the Roman Church hated Marcion, and saw his Canon as a threat. It is almost certain that these "saints" spread lies about Marcion. We know almost exactly what was in Marcion's Canon as a result of these exhaustive criticisms, and considering the bitterness of the Church aginst Marcion it may simply be because his New Testament Canon is the original, thereby exposing the Church's own interpolations of his work.
Note that most of what was written against Marcion was long after his death. It was only when his original Scripture was mutilated that they needed to explain why it was different from Euangelion and Apostolikon.