It's particularly hard to show off the man in WCS, so it's really not suitable for DWTS. I remember the season they tried, the judges criticized Lacey for dancing around her partner while he mostly just stood there. Since Lacey has a WCS background they did a more authentic version than anyone else. To answer the original question, WCS is my favorite with someone who knows how to dance, as it fits most popular music, can be adopted to almost anything, and leaves lots of room for improvisation. But at a club or wedding dancing mostly with ladies who have no training, I find single time ECS and box rumba the easiest to lead them through.