The verdict
Ask your accountant first, because the best choice usually follows what they prefer. If they have no preference, the real decision is team size and country. Pick QuickBooks if you are a sole trader or a very small business that wants to test on a free plan before paying. Pick Xero if you want several people in the books without per-seat charges. Both depend on local fit: VAT or sales tax, bank connections and prices differ by country. For a Dutch business, compare both with Moneybird and Exact Online before you commit.