Is Odoo really that easy?
It's easy to think Odoo is ready to go after a painless, short installation process. Odoo SA works to give that impression. For nearly every scenario, that's not the case.
Businesses are complex and have unique characteristics. Unless you're willing to completely adjust your business to follow the Odoo way, you'll be doing some customization.
Odoo is available in a few deployment models. Odoo Community Edition is free and open source, meaning you are free to deploy it however you like, without paying any fees to Odoo SA. The Community Edition is, however, limited in its feature set. It's true that the core of Odoo Community Edition and Odoo Enterprise is identical, but Enterprise adds on useful modules that most users are likely to require. Also, to get Enterprise, you must work with an Odoo partner - a consulting company who will engage with you on a project or hourly basis to implement Odoo Enterprise in your organization.
There are other Odoo deployment models. Odoo.sh is a turnkey, Odoo hosted implementation. Enter your company name and your credit card, and get a tailored Enterprise deployment just for you. There are serious limitations that make this a tough model to grow over time.
Alternative routes
Although definitely not for everyone, it is possible to devote yourself to Odoo and make the Community Edition work for you. This route requires learning many technologies like Python, XML, GitHub.
The Odoo community publishes many free and paid modules. These add specific functionality to the base Odoo installation. The quality of these varies widely. Treat any add-on with skepticism. Many modules have highly polished presentations, but the underlying code is often suspect.
One alternative is the Odoo Community Association, or OCA. Modules available from the OCA GitHub repo are written to high standards, and include required tests. These tests are run automatically using a cool tool called Runboat. Even OCA modules have some difficulties. The OCA catalog is not well described, so those not steeped in OCA might have a tough time finding the right modules. Fortunately, the OCA members are quite free with advice in forums and GitHub discussions. Expect to put significant time in this topic, though.