We're very pleased with ASP.NET Zero (https://aspnetzero.com/). The best starting point for web applications I've ever found that enables faster time to market. It helped us to build web applications very fast and not dealing with repeating tasks (like user/role/permission management, localization, audit logging, multi-tenancy, UI components, exception handling system..). Its feature richness, ease of use, comprehensive documentation and good support has saved us tons of time&money.