I own the 14mm lens and I can tell you that it is one fine piece of glass. Together with my 20 1.7, it has become the perfect combo for street shooting. I use them on a Panny GF1 and I also use the EVF. This is a great little system that is very lightweight and portable.
The 14 focuses faster than the 20, in fact, quite a bit faster, it seems to me. The images are razor sharp and like many here, I actually prefer a wider lens for street shooting, so I ordered this lens when it first became available. It is a fine lens and I think most street shooters would be very happing with the photos it produces.