Magento Community version is free of cost and you don’t have to pay a dime to continue using it.
You can create additional websites on their own unique domain all in different languages. Each website can have a unique store with its own design.
When you have several hundred or thousands of products, you don’t have to add them one by one to the website. Create a CSV, and import all of them in one go.
You get the ability to let your users sort your products on basis of size, colors, material etc. which can be very handy.
Functionality to manage tags, descriptions, very clean urls, site navigation etc is built in, thus making the framework very SEO friendly.
Magento is compatible with all major payment gateways like Paypal, Authorize.net, 2Checkout, GooglePay etc. as well as shipping modules like UPS, USPS, FedEx etc.
Magento has a very powerful Newsletter Functionality built-in. For more features you can always customize Magento or go for third-party Newsletter systems and integrate with your Magento store.
When you have a multi-store set up, you can manage all your sales and customers from a single admin. This saves you a lot of time and energy.
Based on Zend Framework, Magento is unargueably the most powerful and robust ecommerce open-source in the market today.
For features that don’t come in the package, Magento offers a huge library of Extensions (free and paid) which Magento Developers can use seamlessly with your Magento store and make it even more powerful.