If you're thinking about migrating from QuickBooks Online to Zoho Books, here are some recommendations:

• Make sure to test each type of transaction that you normally have (e.g, invoicing, applying payments, issuing checks, etc.).  This will help you confirm whether Zoho Books is a good fit for your business.
• Don't try to import years of historical data.  This can be very labor intensive.  Focus on loading starting balances and open transactions (e.g. customer invoices, bills, etc)
• Decide how you will handle rounding differences.   It's not uncommon to see rounding differences on customer invoices.   An example would be that an invoice that totals $1,582.77 in QuickBooks Online may round to $1,582.75 in Zoho Books.  These are minor differences, but expect them nevertheless.
• If your plan is to convert to Zoho One, I strongly recommend implementing Zoho CRM before you migrate to Zoho Books.   
• Create an organized plan to migrate your data.   This will save you lots of time.