MVC vs MVCS vs CodeIgniter

Exacltly!
Often I see posts here in the forum asking where to put the business logic, if in the models or in the controllers. And both options don't seem to be the right choice.
Recently I saw some answers about using services, but I did think that it was just another option as CI don't forces you to use MVC.
But now I've found MVCS, it feels the right choice.