>>722293
Huge mix of both there. He was a hardcore Platonist Christian, and Platonists always have fascinating and inciteful theology (examples of Platonist Christians include Origen, Augustine of Hippo, Cappadocian Fathers, Pseudo-Dionysius the Areopagite, Maximus the Confessor, Boethius, CS Lewis, and many more) but Platonism has also created some major heresies, such as Kaballah, Gnosticism, and it informed the most cogent pagan arguments against Christianity in its early years.
Eriugena's work translating older texts was invaluable. His work influenced a lot of great Christian thinkers afterward. That alone makes him good in my book.
Unfortunately, he was a pantheist, which is a heresy. I believe he was controversial for a lot of other reasons as well.
Ultimately, he seems to me like William Blake, one of those characters in Christian history who largely followed his own path, who had a lot of great ideas but people both can not and should not emulate them fully or take everything everything they said as gospel. Origen is almost the same way, but to a much lesser extent.