Sirius is a field-proven technology and a popular Eclipse project created in 2013, used by hundreds of developers and organizations around the world to create domain specific modelers (see the Sirius Gallery for public examples of what has been built with it). If you have to create a graphical modeling workbench for your own DSL, then you know how powerful Sirius is to help you design your own designer based on EMF.
Model-to-text generation has been an early goal of the modeling approach, in order to leverage models for generating source code, configuration files, documentation, etc. In the EMF ecosystem, Acceleo provides this capacity as a template-based language that has been part of the Eclipse release train since 2009.
As a consequence of its maturity, Acceleo has been under maintenance in the last few years, meaning it has also been very stable.