Magento 2.3 is a mature, fully-featured, open-source eCommerce platform with a vast community of developers, module vendors and service providers.
Built on top of Zend Framework, it provides a stable, extensible base for building anything from a medium-sized typical e-commerce store to a heavily customized shopping experience. Multiple integration options are available for integrating with external services, such as PIM, WMS or ERP, using either SOAP or REST APIs. High scalability can be achieved with out-of-the-box support for multi-layer caching (Redis, Varnish) and asynchonous operations (RabbitMQ).
The default frontend stack relies on PHTML with LESS, jQuery, RequireJS and Knockout.js, providing theme inheritance and allowing modules to easily plug into specific views. Implementing a Progressive Web Application storefront is also possible leveraging either REST or GraphQL API, built with either Magento's own PWA Studio (React) or with one of the 3rd-party frameworks (React, Vue.js).
Magento comes with multiple extensive test suites, providing a solid solution for unit, integration, functional/acceptance and performance test automation.
All this comes however at a fairly high operational cost - especially in comparison to smaller, less capable platforms. While Magento 2 can be run on cheap shared hosting, we wouldn't recommend such setup for anything more than a test drive. For production deployment, a proper dedicated server (or multiple servers) should be configured with all supporting services (Redis, Varnish) to unleash platform's full potential.