I used Quickbooks desktop and found it antiquated; create an export and email it to your accountant? No thank you. I then tried Quickbooks Online and it was hands-down the worst piece of software I've ever used. I ultimately landed on Xero, which is "good enough". To echo a number of other comments on this page, my accountants were generally slaves to the software. I actually had to change firms going from QBO to Xero as my existing accountant said they only worked with Quickbooks.

This is all a reminder the current tax system in the US is an unnecessary game made unnecessarily difficult.