I have had these for about a month now so I hope my limited experiences with this product helps you out on your decision to buy.
I wore them to work when I first got them and they seemed to work fine. I didn't really notice the weight being there like I do with ankle weights. Although I did have to laugh at myself when I forgot that I was wearing them and went running up the stairs, discovered that my legs were heavier than normal, and tripped up the stairs. Embarrassing... Anyway, I am at work for 9 hours and I have a 5 minute commute. When I took them off after work, I scratched my legs where they had been for about 20 minutes. They fit so snugly that they left impressions on my skin so that when I took them off, my skin was crazy itchy. I didn't buy a size that was too small because i have to use the Velcro straps to keep them in place. I don't think I could manage to keep them on my legs for any more than 12 hours. I'd scratch my legs to the bone!
I decided to try wearing them on one of my runs. Ran 3 miles with them on and it was a pretty tough workout. They staid in place and didn't seem to bounce around very bad. I'll probably end up just wearing them to workout in or for hikes.
I gave it a 4 for value because you could use these weights in conjunction with ankle weights and because you can wear these "in secret". (I dread they day I get "busted" wearing them though.)
I gave it a 4 in appearance because it looks like some kind of futuristic armor and for it being all black.
I haven't used them long enough to truly test durability so I gave it a 4 because, just guessing, I think they'll last for at least 4 years with average use.
I gave it a 5 in workmanship because they fit my leg really well and i like how the weight was dispersed.