Strengths: Warm, dry, easy to put on, extremely breathable.
Weaknesses: Tricky to get right fit.
Simply a great product. Keeps my feet warm so far down to 30f. No moisture buildup like neoprenes. The inside of these booties are medium weight polar fleece. Seems to conform and insulate well. Outsides are windproof and water resistant. They go on easy and have kept my feet dry and warm through rain and soaking wet dirt roads. I bought the 11-13 size and they fit my 12 Sidi Dominators well. Slightly too tight over my Pearl Alps. Best bet is to buy in person at your LBS and fit them to your shoes.