A conversational debate between Aaron Shafovaloff (evangelical) and Robert Vukich (Mormon apologist).
This video is a great example of why it is important to keep probing when a Mormon apologist seems to affirm traditional Christian doctrine.
Robert was very confusing. Toward the beginning he said God was always God and that he never sinned, but then later revealed that the "never" only applies to the timeframe that we know of, and that there may be a timeframe beyond what is in our current view where he had to become a God and where he may have sinned. In fact, Robert went on to say that if "theosis" (as Mormons define it) applies to us forward, then it probably applies to God backward (i.e. God went through theosis).
He also equivocated on the issue of whether God was once a sinner, sometimes insistent that He never sinned, sometimes insistent that no one can really know if God sinned.