BILL, which most people still call Bill.com, is not accounting software. It sits next to your accounting software and takes over the part everyone hates: receiving bills, getting them approved by the right person, paying them, and making sure the entry lands correctly in the ledger.
The problem it actually solves
Below about fifteen bills a month you do not need this. Past that, the manual process starts costing real hours and producing real errors: invoices sitting in one person's inbox, approvals chased over text message, and a payment run that means signing checks. BILL gives every vendor invoice a route, a record and an audit trail.
The centralized inbox is the part reviewers describe as the turning point. Vendors email invoices to one address, the system reads them, and they queue for coding and approval rather than living in somebody's email.
The sync is the whole argument
Two way sync with QuickBooks and Xero on the Team plan, and with NetSuite, Sage Intacct, QuickBooks Enterprise and Microsoft Dynamics on Corporate. If the sync to your specific ledger is shallow, most of the value evaporates, so confirm your exact edition before signing rather than after.
Where it frustrates people
Per user pricing is the recurring complaint. At 49 dollars per user per month on Essentials, a finance team of four is close to 200 dollars a month before anyone has paid a bill, and approvers count as users on the lower tiers. The math works when it replaces labour and looks poor when it does not.
The other theme is payment timing. ACH transfers move on BILL's schedule rather than instantly, and reviewers who did not plan for that have been late paying a vendor while believing they were early. Learn the timing in your first month, not your fourth.