I use GnuCash and OpenOffice.
GnuCash is quite powerful however it is rather heard to learn. I expect that's because its instructions were written by software engineers.
Before I figured out GnuCash, I kept my checkbook in OpenOffice. Now I use OpenOffice just for budgeting. I have a really good method for it that my ex-wife figured out, and that I expanded on.
I've been intending for eons to write up my method.
I don't use QuickBooks for business finance because it charges money to download the US IRS and state tax tables. Those are provided free of charge, at considerable taxpayer expense, by the tax authorities, yet Intuit has the gall to charge, and of course the QuickBooks tax tables are in an undocumented format.