I haven't used it, so not sure if it fits the pattern, but the question for me is: is it useful, time-saving, more usable? does it make the task more clear for the programmer that uses it?
It depends. It is a fundamentally different branch of the OOP family tree than what most people are used to seeing. Enough so that I've seen people declare it to *not be OOP*. So if you stumble across the model having only seen the style of OOP popularized by C++ and later Java, no. You will probably *not* find it to be liberating.
The idea is that you have classes which model state. And then you have generics that model functionality. And you define methods which provide an implementation of the generic for a class. But it's more flexible than what you see in Java because such a method can be easily added after the fact as it's not intrinsically part of the class' definition.
If you're familiar at all with Typeclasses in Haskell & Scala, personally I find those to be similar enough to get the gist. Likewise Dylan and R's S4 objects are modeled after CLOS' structure.
