MERN and MEAN stack are among top technology stacks right now. Both are very good options having some specific strength and considerations depending on the technology needs of the project.
The difference between both technology stack is that in MEAN stack it’s Angular and in MERN stack it’s ReactJS as frontend technology, respectively. Angular is a framework and ReactJS is more of a lightweight framework/ Javascript library.
Talking about their usages:
- MEAN stack is great when it comes to scalability since it has the foundation of Angular based web framework. MERN stack is great when it comes to real time data driven projects thanks to it’s real time ReactJS libraries.
- MEAN stack is more suited for medium to large size projects. MERN stack is more suited for small to medium size projects.
Again these are theoretical generalizations and not hard rules.