MEAN isn't as easy to set up and I would not compare it to Rails at all. Rails is a backend framework—MEAN is just a bunch of technologies used together to have an API and a SPA. I'd actually argue, from personal experience, that newbies have a lot of trouble with MEAN because while there's a CLI tool MEAN doesn't have the community support, conventions, etc. that Rails does. Plus, you have to learn too many things at once.