These Pear Izumi booties replaced a pair of neoprene covers which finally failed due to a torn zipper.
All in all Im reasonably impressed with how well these new ones work. Entry and removal are much easier due to the two Velcro-like fasteners on the back. The covers have worked great in low 40 degree temps while wearing alpaca or wool sox. One thing I have finally learned (which no one ever shared with me) is that circulation trumps insulation. Leaving ones shoes looser in the winter in concert with a good set of shoe covers does wonders in keeping those toes more comfortable.