Having ordered snow chains during a period of heavy snow last March, the chains arrived when nearly all the snow had gone! This year, however, I had them when I needed them and did I need them! We would certainly have been snowed in at Sporting Scotland without them.
So how have they fared during this past month of constant snow cover on Speyside. The quality, being Chinese, is not the best. I noticed quite a bit of wear on them after about 30 miles on half-cleared roads plus some of the links wore out which made the chain brake. Enough spare links fixed all these little problems. I remember from my times in the Alps that we did not remove the chains for 5 months and the chain would rather "eat" the tarmac than the other way round!
After some research and talking to friends in Bavaria and Austria, it seems that the German RUD and the Austrian PEWAG are made for the job and they will last - they also are reversable, which doubles their lifespan.
No problem getting through these drifts with the snow chains.