We're trying to cover two main use cases: API apps and full stack web applications. There are features in Rails that we recognize to be really useful. For that niche we're trying to be a lightweight alternative.
Why should I use lotus over Sinatra, Padrino, Grape, Rails, etc?
Speed, control, testability and maintainability.
I'm giving Lotus a try for an api. I'm looking for something a little more lightweight than Rails. I'm hoping for a fun experience.