We didn't want to pay the upcharge of about $300 a year for a complete payroll service but wanted help with the taxes (we are in VA and our nanny lives in DC and I did't want to deal with it). We went with the least expensive 4nannytaxes solution.
They remind us by email when we need to do things, they helped us when the tax rates changed this winter, and we find them very easy to work with. The paperwork they gave us at the end of the year was easy to feed into Turbotax too.