Too Long; Didn't Read
The decision to choose a tech is crucial, which will probably define how your app is going to be. There are few cases in which you shouldn't even consider using Ruby on Rails. If you want to build a prototype of your app, use Ruby on rails to get it out quickly and build it secure and easy to read code and build only what matters and leave the rest to the pros. The power of 'convention over configuration' approach can really be seen when you are building a prototype.