There are two main differences: Baha'i believes in one universal God and is based on the prophet Bahá'u'lláh's revelations; universalism, founded at US universities, allows for many definitions of God.
Bahaism teaches the Oneness of God, unity of all faiths, the inevitable unification of humankind, yhe harmony of all people. Universalism is the belief that all people will be saved.
Bahai's belief is truly different from any other religion. Basically followers of other faith also may have similar outlook. I woudl say, the followers of other faith thinka bit narrowly about their own religion and faith. But Bahai's keep this quite open and wish to have an ultimately unversal and single stream thinking. This will surely do good for world