Three fair comparisons for the person who has to know by Thursday whether the nursery, the sound booth and the greeter door are covered on Sunday.
Most small congregations do not choose scheduling software the way a large church does. There is no committee and no rollout. There is one administrator, often part time, who inherited a spreadsheet and a group text thread, and who needs the serving rota published far enough ahead that a volunteer can plan a vacation around it. That is the person these comparisons are written for.
The tools below are all real and all used by American churches. They are built on different assumptions: one sits inside a full church platform, one grew up scheduling parish liturgical ministries, and one is a general signup sheet used by schools and sports teams as much as by churches. None of them is wrong. The question is which shape matches a Sunday morning with sixteen serving slots, a bench of volunteers who can give one Sunday a month, and a coordinator who does not want to spend Saturday sending texts.