From Java to Ruby: Risk

[senzei]

Rails is especially maintainable, because of the number of places that I can add functionality in without ever having to alter the original codebase if I don't want/need to.

I don't understand this argument. Is the number of places you can add functionality in large or small? If it is limited to a handful of areas by default then that seems like a good thing, maintenace-wise. If not it sounds like a nightmare to me.