I have been using Xero for a few years now.
Bank feeds keep disconnecting.
No customer service phone number. Messaging service can take hours to get a generic answer, then back and forth many times as you can't speak to someone to resolve quickly.
Paying a large number of invoices at the same time is very difficult. If you need to go to the next page or check an invoice you will lose all selected invoices.
Lacking basic accounting features such as adding interest to late payment. There is no automatic feature to calculate and you can't add to an approved invoice or one that has a payment attached without first removing all payments made, adding the manually calculated interest then reapplying all of the previous payments.
There are more issues, but, in short, this is an easy program to use for small businesses ONLY but lacking in basic accounting features and customer service.