So your kids are in school age. Do you already know where they will be going to school? Public? International? The distance to the school might be an issue for your preferred location of living.
For public transport, there is a tariff-boundary between Eschborn and Frankfurt. If you plan/will live in Eschborn, then you will need either an more expensive monthly ticket or you will have to pay extra for every travel to Frankfurt. Eschborn Süd is just on the tariff-boundary, meaning that this station belongs to both areas. For details, pls. have a look at the
Gesamtlinienplan Frankfurt. More information about the public transportation can be found at the webpages from the
RMV.