I saw a test comparison between the knock offs and the maxtrax. The knocks offs are basically a use once. The problem is, you may have to use a set five of six times to get out of a single situation. So the knocks off may have the grips worn off before you even get out. If I am going to take up the room for a set of maxtrax, they are going to be the real thing.
On a side note, I'm not sure if it was on here, youtube, or fb, but there was a writeup where a tc up in Yukon territory ran off the road when the side of the road gave way. The driver was smart enough to drive on down off the road so the truck stayed upright. The ground was so soft, without the maxtrax to help provide support, the two trucks with winches that stopped to help, probably still wouldn't have been able to get him out.
