Odoo is a suite of apps that share one database: accounting, CRM, inventory, manufacturing, ecommerce, field service and about 40 more. You enable what you need and the rest stays out of the way.
What it does well
Breadth at this price is unmatched. A manufacturer running Odoo gets a general ledger, purchasing, inventory, a bill of materials, work orders and a customer portal that all reference the same records, with no integration to maintain between them. That is the argument, and for the right business it is a strong one.
Being open source, the Community edition is free and self hostable, and the code is there if you need to change something.
Tax and filing
US sales tax works through an Avalara integration. Canadian GST, HST and PST are supported natively per province. Odoo is a system of record: it prepares numbers for your accountant and does not file with IRS or CRA itself.
Where it frustrates people
Implementation is where the money goes. Licensing looks inexpensive and then a partner quotes a five figure project, because configuring a suite this broad is real work. Budget for it or do not start.
Upgrades between major versions are a project when you have customizations, and reviews describe being stranded on an old version because upgrading was too expensive. Partner quality varies a lot. Choose the partner more carefully than you choose the software.