It all depends whether you think religion is about beliefs, practices, or values. It is often stated that Wicca is an orthopraxy, not an orthodoxy. Nevertheless, if you think it is about beliefs, I still believe the same as many (if not most) Wiccans. I believe that the Divine has one substance (the mind of the Universe) and many forms (individual deities). I believe that the Divine is immanent in the Universe, and includes feminine forms, masculine forms, and forms without gender.
If you think it's about practice, I am still practising Wicca, and haven't modified that practice.
If you think it's about values, I still share the values of Wiccans (though it's less clear to me that Wiccans actually do have a set of unanimously shared values - some covens are hierarchical, others more democratic, some are consensus-based). But my values are pretty much the same as they always have been.
Then there's the shared history of Pagans and Unitarians. One early Unitarian was Iolo Morganwg, who is better known in the Pagan community for being one of the founders of the Druid revival. He was also one of the founders of the South Wales Unitarian Association, and wrote hundreds of Unitarian hymns in Welsh.
Another Unitarian writer who influenced the Pagan revival was Ralph Waldo Emerson. Although he fell out with the mainstream of nineteenth-century Unitarianism, he had a profound influence on 20th-century Unitarianism. He also wrote about the concept of polarity, an idea which is very important in Wicca.
POLARITY, or action and reaction, we meet in every part of nature; in darkness and light, in heat and cold; in the ebb and flow of waters; in male and female; in the inspiration and expiration of plants and animals; in the systole and diastole of the heart; in the undulations of fluids and of sound; in the centrifugal and centripetal gravity; in electricity, galvanism, and chemical affinity.Emerson had been influenced by Rammohun Roy, the Indian liberal who campaigned against sati (widow-burning). Emerson in turn influenced Edward Carpenter, one of the founders of the Pagan revival, the poet Walt Whitman and the writer Henry David Thoreau.
Unitarianism has a thriving Pagan element, represented in the UK by the Unitarian Earth Spirit Network (founded in 1990), and in the US by the Covenant of Unitarian Universalist Pagans (founded in 1987). The first known Pagan UU ritual was in 1980. Unitarian Paganism and Unitarians' positive attitude to the Goddess is also mentioned in Margot Adler's book Drawing Down the Moon. Several Unitarian ministers are also Pagans; and many of the hymns are about nature. I am by no means the only Wiccan to join the Unitarians; I have heard of several others.
Unitarians were also the first denomination to have a woman minister, Gertrude Petzold, and the first to include LGBT people; Dudley Cave, a Unitarian, was a founder of the Lesbian and Gay Switchboard.
Last but not least, Unitarianism includes material from other religions (and has done so since at least 1850). The UUA includes these in its principles and sources.
If after all that, you're still wondering what attracted me to Unitarianism... well, I rather like Yeshua (even if he didn't actually exist), in spite of the terrible things done in his name, and I like the liberal values of the Unitarians.