According to a recently published research paper co-authored by researchers from Drexel, NYU, and the University of Washington, Tor users make high-quality contributions to Wikipedia. And, when they are blocked, as doctoral candidate Chau Tran, the lead author describes, "the collateral damage in the form of unrealized valuable contributions from anonymity seekers is invisible."
I haven’t contributed to Wikipedia for a few years now because of sanctions against anonymous users.