Lisp: Productivity?

From 'Practical Common Lisp':

"If you think the greatest pleasure in programming comes from getting a lot done with code that simply and clearly expresses your intention, then programming in Common Lisp is likely to be about the most fun you can have with a computer. You'll get more done, faster, using it than you would using pretty much any other language."

So /prog/, do you agree?

I am not very familiar with lisp but I have decided now that I am going to spend some time learning it. I just want to know whether this statement is complete bullshit or not, before I get started. Even if it's not true, I still want to learn lisp.

I mean, I'm sure I could be more productive in CL than in, say, C, but what about compared to Ruby or another such language, which frankly make me frighten myself with my own productivity.

Discuss.

I just downloaded Practical Common Lisp and On Lisp. PCL has some chapter-sized example programs in it. I'm still looking for real examples from Paul Graham.

My first introduction to Lisp was back when XLisp/Winterp came out and my co-worker wrote a Motif GUI database form MUCH faster than anyone could do it in C++. The code was half a page. All our jaws dropped. But we couldn't talk the boss into switching even a little part of the system to Lisp. (I would still have that program if CD's didn't die sitting on the shelf.)

So, to me, it's not a question of whether Lisp is better, faster, and smaller. I know it is. I just need to see more examples from professional, in-the-trenches programmers who really know what they're doing and write practical Lisp apps.