I've actually looked through the code of it, and there are parts of it that I find a tad excessive. Live if you name your model "Tags" then it will automatically associate it with a controller class called "TagController" and it will associate it with a particular 'tag' table in the db... But all of this is done through functions that try to 'singularize' a plural word, or 'pluralize' a singular word.
I think this is a little much to run through in a webapp. If it was something that was run through just once, that's fine. But this is run through a lot. I don't like this trade-off of inefficiency in order to make things easier.