Strengths: In general they are very comfortable. The grip is second to none on trails, snow, mud. The seem quite durable, especially given the terrain I run on. The price is worth it as I don't have to think about my feet once I put them on. I can say that about all Salomon products (tops and tights also).
Weaknesses: Occassional and breif numbness in feet due to harder chassis, however this only seems to last for 1-2km and certainly not on every run.
Overall: Another top end Salomon product. I researched these for some time and wasn't let down. It is advisable to buy 1/2 a size above your norm.