Customer Q: With ACH do we, as the contractors get complete payment? Or just part of it?

Answer: (Hopefully I am understanding this question correctly - let me know if not!)
When your customer pays via ACH Bank Payment, you receive the entire amount they've paid into your account. There is a 1% fee for this payment method. 
If you toggle on partial payments on an invoice, your customer can opt to pay the invoice amount across different payment methods (ex: split between two different credit cards, or part credit card and part ACH payment). They could also only pay for part of the overall total. However, they will still receive reminders that they have an overdue invoice until the entire invoice amount has been paid. 
You can find more detailed instructions with screenshots here: https://help.getjobber.com/hc/en-us/articles/360033907753-How-to-Collect-Payment-on-an-Invoice#h_01JBYN7A460W8TE1WGJ4JBB2Y9