I have no information for SMF 3.0 and differences from 2.0 but Joomla 1.5 needed a
migration, not upgrade, from 1.0.
Also SMF is UTF-8 ready since 1.1 RC3 and has incorporated converter.
So, I find SMF more user friendly than Joomla. There are different approaches, Joomla is a successful software, that doesn't mean that every decision for his development was the only and the best.