After waffling for several weeks, I finally placed my order for the Panasonic 20mm last week. It just arrived today and I'd like to share my first impressions. Hopefully this will help my fellow wafflers out there! 

Pros:

• light, compact, well damped manual focus (far better than the kit zoom)
• nice shallow depth of field shots with great bokeh--gives all your pictures that "SLR" look
• viewfinder very bright and snappy with this lens
• excellent sharpness (only pixel peeped using viewfinder so far)

Cons:

• aperture blades are indeed noisy! You hear the "click click" of the blades as you move about.
• still fairly noisy AF motor, though it is quicker and quieter than the kit zoom; noise definitely audible in videos
• C-AF is noticeably slower to find focus than using S-AF (I would call it "leisurely"), but again, it's better than the kit zoom

Bottom line: is it worth the money? Hard to say at this point, considering this one lens cost nearly as much as my E-P1 + kit zoom, and it's 50% more than the Olympus pancake. But I suspect I will not regret the purchase. (I may after Photokina, but I hope not.)

No, I haven't. I carefully considered the 17mm but then decided that I would kick myself in the future if I passed up on the Panny, especially since this one place sold it for $80 cheaper than all the other places. To me, the sting of passing up on a fast, super sharp prime would more than outweigh the one time discomfort of spending a few more $$$ for it.

And I just realized my math was off: the 20mm is almost 50% more than the 17mm when using the prices of the big camera vendors in Canada ($499 vs. $349). The retailer I got it from was only 20% more ($419 vs. $349), so I guess it's worth it!

The U.S. price on these things is about $370, which is still pricey but at least you can get free shipping in the States. I still had to pay $22 for the least expensive shipping option!