Do not pick software to avoid a rebuild
I get asked QBO vs Xero by firms whose real problem is two unfiled years.
Software choice does not reconstruct a dead file. Bank statements do. If the history is the issue, read dead QuickBooks file reconstruction and use tax deadline reconstruction. Then pick the going-forward platform.
What I actually care about
Can we get statements and a clean current file? Is the firm standardized, or is every client a different stack? Who reviews exceptions?
QBO is still the default in most US firm books I see. Xero is fine when the firm already lives there. A mix is workable if the chart, naming, and review rules are written down once. A mix with no standards is how 90-minute review becomes a scavenger hunt.
What firms get in a monthly package does not change with the logo on the login screen. Sample deliverables is the pack either way.
Data drops are a different product
If the "software" is CSVs in an email, that is not QBO vs Xero. That is a data-drop workflow, and it is a weaker starting point for monthly delivery. Reconstruction from statements may be cleaner than pretending a folder of exports is a ledger. Reconstructing books from bank statements is that path.
BLS still describes the job as keeping complete records. Complete records can live in more than one system. They cannot live in an inbox.
How I would decide inside a firm
Standardize when you can. Do not force a conversion in January. Tax season bookkeeping capacity is the wrong moment to migrate 40 files.
For monthly white-label, start at For CPA Firms and run a free test client on the platform you already use. Onboarding a white-label partner is the first 30 days.
The Journal of Accountancy offshoring guide is still useful on structure. Software is a detail. Review ownership is the product.
Start a free test on the file you already have. Do not wait for a perfect stack.