Maciej Wisniowski, a full-stack web developer at Orbitvu, is using FusionAuth as an OAuth2/OIDC/SAML server to provide login and SSO to various applications. He leverages FusionAuth's API for internal integration with other systems like ERP and project management software. The benefits of having one view of customer accounts across multiple applications include seamless switching between apps without logging in, centralized user account management, and secure integration with external providers. FusionAuth offers flexibility, competitive pricing, and customization options, making it a cost-effective solution compared to competitors. Maciej appreciates the product's development style, GitHub issue tracker, and support community, which feel like an open-source project despite not being open source itself.