It sounds a lot like Universalists were, historically, better people than Unitarians.
Thomas Starr King summed up the difference: "Universalists believe that God is too good to damn people; Unitarians believe that people are too good to be damned by God."
I'm going to now try and construct a historical timeline of the two faiths for my own study, cobbled together from a variety of sources I'll list below.
(1) Origen of Alexandria, who lived from 185 to around 254 CE, wrote on the unity of God and Jesus' love of humanity. He argued for no Hell and for a benevolent God who would offer a universal salvation. This would be the foundation on which liberal religion was built.
(2) The Nicene Creed, adopted 325 CE in what turned out to be in many ways a political, not religious, act, codified the Trinity (the Father, the Son, and the Holy Spirit). The people who rejected or questioned the Trinity, Unitarians, were then considered heritics.
(3) In 1553, Michael Servetus was burned at the stake for his pamphlet "On the Errors of the Trinity." He stands as the most famous Unitarian martyr.
(4) Unitarian ideas began to spread across Europe in the late part of the 1500s. The first official Unitarian church was established in 1568 in Transylvania, where the seeds of religious doubt had been sewed by a Unitarian king named Sigismund.
(5) Anti-Trinitarians gained steam in the 17th and 18th centuries, and by the end of the 18th century, 20 Unitarian churches existed throughout England. Milton, Newton, Locke, and Nightingale were all thinkers who expressed support for the Enlightenment principles of religious freedom and tolerance.
(6) In 1759, the Englishman James Relly published "Union," which claimed that all would be saved, a refutation of the Calvinist view of salvation for the few. This was an expansion and definition of the Universalist doctrine.
(7) A Relly follower named John Murray brought this Universalist vision to the United States (which, actually, didn't exist yet under that name.) 1779 saw the establishment of the Independent Christian Church of Gloucester, Massachusetts, America's first organized Universalist church. Later, Hosea Ballou, a devout Universalist, wrote "A Treatise on Atonement," a strong argument against Hell and miracles and a contemptuous God.
(8) Joseph Priestly, best known as the discoverer of oxygen, also helped bring Unitarianism over here. He was a Unitarian minister who'd been harassed and nearly killed in England for his views, and in 1796 he opened the first Unitarian church in America in Philadelphia. By then, liberal religion had gone beyond a mere rejection of the Trinity to a more widespread and serious skepticism about fundamental doctrines of the Christian establishment.
(9) People like Clara Barton, Julia Ward Howe, and Susan B. Anthony were guided by their liberal faith to champion such social justice measures as abolition, women's rights, and prison reform. Thinkers like William Ellery Channing, Theodore Parker, and Ralph Waldo Emerson preached the liberal gospel in sermons across America. The two paths of liberalism had grown even closer.
(10) In 1785, the first step was taken toward the establishment of the Universalist Church of America. Spring of 1825 saw the establishment of the American Unitarian Association.
(11) Finally, on May 11, 1961 the two faiths merged to form the Unitarian Universalist Association of Congregations in North America.
Okay, so this post turned out to be almost entirely a slight paraphrasing of Gary Provost's illuminating article for the UUA, "A Brief History of Unitarian Universalism." So I claim no original thought in anything above, but I do think it was a good exercise for me; now that I've written out the information, the odds seem much better that I'll retain it.