I have been using GnuCash for a while and really like it. True double-entry bookeeping and none of the bloat the QuickBooks has. Getting checks to print correctly was a byzantine few days but this is something you only need to do once so hey...
On an email list, there was mention of SQL Ledger as being more of a large ERP application. Looks interesting - been in development for more than ten years and it's last release was in April of 2017 so it is under active development. It is written entirely in PERL and runs using a SQL Server as its backend. No mention of speed (running an interpreted language) but still, the feature list is quite comprehensive. Here is the feature list from their website
Accounts Receivable, Accounts Payable, Vouchers, General Ledger, Inventory Control, Billing / Invoicing, Payroll, Time Cards, Recurring Invoices, POS, Check Printing, Purchase / Sales Orders, Customizable Taxes, Multi-user, Multi-company, CMS, Audit Control, Foreign Currency, Internationalization, Access Control, SQL server backend, Customizable Templates, Customers, Vendors, Assemblies (BOM, kits), Chart of Accounts, Customizable Reports, Memorize Report Layout, Financial Statements, Export Payments File, Administration Module, Application Interface, Backup to file/email, Import transactions, Use on Handheld, Document Control
Have to download it and give it a try when I have nothing else to do and feel like dinking around with a new application.