I took a couple of packs of the new Polaroid PX 600 Silver Shade film with me to Italy. As many have described, it is a very finicky film to work with. The main issue is that it is VERY light and temperature sensitive. If exposed to sun during the development process, images come out somewhat overexposed to completely blown out. The solution is to cover the film as it comes out of the camera and then allow it to develop in darkness. I simply used the dark slide to cover the film as it came out (unfortunately I didn't have gaffer's tape to tape it to the camera) and then stuck it in my pocket for 3 minutes to develop.
Sometimes the flaws of the film really add to the nostalgic quality of the images. And sometimes they don't. I'd say I had more misses than hits, but I love how the images that worked out look like they were taken in 1910 rather than 2010.
The other problem with the film is that there are many reports of the developed images fading and forming what have been dubbed "killer crystals". Alas, this happened to mine. Luckily I scanned in the best images shortly after I returned from my trip. But those that I didn't scan have faded away into the mists of time. The Impossible Project has posted tips on how to store and care for developed images to avoid this problem. The chemistry of this film still needs work, but in some ways, I like its unpredictable nature. To paraphrase Forrest Gump, "Silver Shade film is like a box of chocolates. You never know what you're gonna get".