Dan Dittmarwrote a review of Western Mountaineering Down Bootie on November 24, 2014
Familiarity: I've used it several times
Fit: Runs large
Ultimately choose these over the flash bootie. They have a bit more foam in the footbed and seem a tad more durable all around. The slight weight gain in these is worth it for me for the extra toughness and warmth. There is also more grip with these over the flash booties. My shoe size is a 10.5 so I should ideally fit perfectly in the Large. I didn't find this to be the case, they were too big and felt sloppy because of this. After sizing down I am very happy.