I didn't have time to write a short review for the VFF Performa but I've finished the long review for these shoes for the Living Barefoot website.
Check it out at:
http://www.livingbarefoot.info/2009/10/review-vibram-fivefingers-performa/
In case you've ever wondered what I sound like, there's also an audio version of the review. This is something we're going to continue with for future reviews. It's available for download on the site above or through iTunes via The Living Barefoot Show.
In (very) short, the Performa is an outstanding addition to the VFF lineup. It is definitely my choice for an indoor minimalist shoe. They are surprisingly warm, extremely comfortable, weigh a scant 50 grams, and have the best barefoot feel of any shoes I've tried so far.