In this final two months of testing (and sometimes merely hoping to test the Yaktrax Pro), I have carried or kept the devices handy for dayhikes, travels out of the area, daily use in snowy conditions, and three short local (Eastern Massachusetts) overnight trips. Conditions have ranged from the low 20's F (-7 C) to about 60 F (16 C) in both city and rural flat to hilly terrain. We were experiencing a "snow drought" for the end of winter 2006 and the beginning of the winter season of 2007, but have finally had several weeks of snow, ice, and slush.

I have been really happy with the Yaktrax. They are easy to pull on over my light hiking shoes, women's size 11 (US), and only a little difficult to affix over my heavier, insulated men's size 10.5 (US) boots. They have not come off unless I wanted to take them off, except once.
On the occasion that one Yaktrax popped off, I was wearing them over the heavier, bulkier boots, without the extra top-of-the-foot strap. I was driving my personal vehicle between a very slippery driveway and my even more slippery workplace. I didn't bother to take them off to drive to work, as it is a short distance. I could feel the Yaktrax between my shoes and the gas and brake pedals, but they seemed to pose no hazard for the tiny trip. I didn't immediately realize that I'd lost the Yaktrax until I walked part of the way into the building, as the snow was only slippery in places. It was easy to "back-track" following the criss-cross pattern of only one foot. Apparently working the pedals and moving my foot to the rubber mat somehow worked one traction device loose. From that point on, I didn't use the Yaktrax Pro without the top strap.
For around town, when the sidewalks and parking lots were unplowed, I felt very secure walking on snow and all but the hardest slick ice. Really hard, shiny ice sometimes was still slippery to walk on. I'm not sure "crampons" would work on ice that hard and slick. The cheap instep crampons I tried some years ago just flattened out when I tried to walk on such rock-hard ice. I haven't used good crampons to know if these would have worked in that circumstance. The times I walked into the building from early morning student arrival duty, it was almost comical that I had such sure-footedness in the packed snow in front of school and then felt as if I were walking on a skating rink when I walked across linoleum flooring to a seat. As I removed the Yaktrax, I came to the realization that the instructions to remove the traction devices indoors, perhaps were more for personal safety than for floor surface protection. ("Duh!" on me.)
The metal coil over rubber design of the Yaktrax allows for ease of carrying in anything from a daypack to backpack to luggage. I've had two trips out of my area that involved flying. I didn't have to worry about the coils digging into other packed items, whether in luggage or my packs. The only "hassle" came from my husband who was curious as to why I would want to pack the Yaktrax when we flew to Las Vegas. No, I didn't want them for Las Vegas, but they are light and compact enough to carry in the likely prospect that we arrived home early on a winter morning to find ice in the Boston area. Carrying them to Ohio in January was a bit of wishful thinking, perhaps. It was snowing as we left to return, so that was yet another time I carried the Yaktrax without actually using them, this time in a carry-on bag. Again, they were easy enough to carry that I didn't mind the weight penalty versus the insurance against a fall. Happily, airport security did not find them objectionable.
For trail use, they are convenient to carry, as stated, easy to pull on, and to remove. I found the Yaktrax to be a good aid in slush, light snow cover, and icy conditions, as opposed to sheets of glare ice. The coils held up in mud and over rocks and helped with my "footing." Mixed ice and rock areas were no problem for traction. I happen to have some permanent nerve damage in one leg and foot, so I can't really feel what I'm putting that foot down on. This makes it really easy for me to slip and fall. I didn't do so while trekking in Yaktrax. I'm wondering now if they would be helpful for crossing streams over algae-covered rocks this spring. Hmm! They wouldn't be much of a burden to carry and would be quick to put on if I decide to check this out.
Things I like about Yaktrax-
-Easy to carry
-No damage to other items in packs
-Lightweight
-Compact
-Easy to use
-Quick to affix and to and remove from shoes or boots
-No hassle getting through airport security
-They work!
Things I didn't like
-Um, once the "rubber smell" dissipated, what's not to like?

For hiking in shallow snowfall, muddy or icy conditions, the Yaktrax worked very well for me. I did not try them in deep snow, where snowshoes would be more appropriate, and for which the Yaktrax were not designed. They were equally helpful on the trail and in town. I found them light enough that I did not object to carrying them "in case" I needed them: This is a big leap for a lightweight backpacker. Would I recommend them to others? Yes. My pregnant supervisor expressed her worry about falling on ice in her "delicate condition," and I, of course recommended that she consider purchasing a pair of Yaktrax. This may be the first winter in over 10 years that I not had even one fall on snow or ice.

Thank you, Yaktrax!

And, thanks to Backpack Gear Test for this testing opportunity.