I really think that the best metric is size, as in lines of code, like the article seems to to suggest. Personally I may even be tempted to use bytes.
For obvious reasons, number of features correlate with size, but I also noticed that bad code tends to be too big for the little it does. Dead code, repetition, rewriting functions that are already available because you don't know your API, etc...
Note that it is a metric, not a goal. Making your code smaller won't necessarily make it better (ex: minification), but big code is more likely to be bad and successful efforts to make it better will most likely make it smaller.
For obvious reasons, number of features correlate with size, but I also noticed that bad code tends to be too big for the little it does. Dead code, repetition, rewriting functions that are already available because you don't know your API, etc...
Note that it is a metric, not a goal. Making your code smaller won't necessarily make it better (ex: minification), but big code is more likely to be bad and successful efforts to make it better will most likely make it smaller.