I have a pair I bought for my own use, plus a pair of boot chains provided by my winter employer.  The Yak Trax look to me as not having as long a life as a good set of chains.  My Yaks have had a couple of the springs break into two pieces.  But then again, when I wear them I wear them all day sometimes for several days in and out of trucks, across any surface (except customer's hardwood floors).

RUD bootchains are about as good and seem to have a longer life.  But DO NOT buy knock-offs.  Get ONLY GENUINE RUD chains

 Boss orderd some one time and the supplier had some a lot cheaper but "just as good".  They were Made in China knock-offs.  The links were a softer metal and not welded (the RUD has each link welded shut).  They would not make it through the day without breaking.

I've thought about getting them for the firefighter's turnout gear, but can see potential problems with the YakTrax or chain in a fire situation.  I don't think the rubber will take the heat and can see them being a hazard even if intact, as the chains might catch something and trip a firefighter.  I am thinking of getting a couple sets of chains in the pumper and tanker so they can be slipped on by the operators if needed.

edit:  I found this in a Google search, but he didn't offer much more than "My new Yaktrax didn't hold up very well after just one hike."  Looking at the article and where he had taken them ... that is not such a bad testimonial.