[jly]

This is something I manage pretty easily without a lot of fuss using a spreadsheet and one bank account with my 1099 business. I do a small volume of transactions with higher dollar values, so this might appeal more to high-volume businesses where the manual effort increases a lot.

I would be more interested in hooking in to the paying and calculating quarterly estimated tax payments.

Will this system do sales tax saving/payments? I pay those quarterly to my state just like the IRS estimated income payments and treat them essentially the same from a management standpoint. Any third-party system would need to be flexible to handle that, as well.