For me it was that IFTTT allows only one IF condition and one THEN step, whereas Zapier allows more simoltanous IFs & then THENs. IFTTT is free, & kind of have

For me it was that IFTTT allows only one IF condition and one THEN step, whereas Zapier allows more simoltanous IFs & then THENs. IFTTT is free, & kind of have no limit, whereas Zapier allows only 100 executions of your zaps in a month.