No, I don't think Unitarians are prone to it, though modern Unitarianism (in both the Socinian and Feathers Tavern senses) exists in a context removed from Arius, though I don't know enough about either offhand (and am meant to be concentrating on revising Jefferson this morning, so I can teach it this afternoon...) to rule. Nor have I discussed theology with a modern Unitarian either, though I'm not sure that there are all that many around. I remember Richard Harries being reported as urging non-Trinitarians to convert to Judaism as Unitarianism was now as good as defunct...