I've got deep respect for the authors, but I've had a pretty miserable experience with Yeoman so far, even after giving it another try this morning. In particular:
* Using the web app generator seems to download an absurd number of dependencies every time. It takes minutes to download everything to start a simple app, about as long as it takes me to install Rails from scratch on the same system.
* After generating an app, I've yet to be able to actually run grunt on the result ... it always errors out with something. If it's not a jshint warning that causes it to abort, it's a Compass warning.
One of the great joys of writing HTML5 + Javascript apps is that the experience tends to feel clean and unencumbered. So far, Yeoman has done nothing but make my workflow much more complex and error-prone. Things just feel ... rickety. At the end of the day, I gave up and used Initializr [1] to start the app. Didn't even want to bother trying out Brunch [2], I was so frustrated.
I wanted to love it and I know there are folks out there who've had great luck with Yeoman; hopefully some of them can chime in to tell me what I'm missing.
[1] http://www.initializr.com/
[2] http://brunch.io