Steve MacCoun says:
"Haskell will change the world...one type at a time!"
Francisco Chaves says:
"I love programming in Haskell because the code is small, readable and maintainable. It enables the identification of most of the bugs at compiling time and their fix at the implementation stage with ease. Haskell's type checker is useful not only for finding bugs but also for developing difficult parts of missing code -looking at the type reported by the type checker with the typed holes feature-. These Haskell type system capabilities decrease dramatically the debugging time compared with other programming languages I have used. As a consequence, the code that I have had to maintain on almost every commercial application that I have developed in Haskell was only for adding new functionalities, not for fixing defects.
The type class derivation mechanism, generics, and templates allow Haskell to generate, automatically, specific pieces of code for data-type definitions such as equality test, order comparisons, conversion to and read from JSON format, etc. Furthermore, Templates combined with Quasiquotes allows Haskell to incorporate extensions of the language (EDSLs) to describe URL routes, data models, and dynamic HTML -among others- with the automatic generation, at the same time, of associated parts of code such as data types, database access commands and HTML interpolation integrated with the Haskell code in a type-safe way. At last, but not less important, there is an extensive Haskell community and a huge base of available, general purpose, libraries, and tools."