These needles are a disappointment. Very cheap plastic, they almost feel as they will come apart, there is a reason that the manufacturer assures that they are 'reinforced for extra strength'. They are pointy and if you are lucky, they will split the yarn, and leave traces of it in the project. If you are a fast continental knitter, you will also find that they have a tendency to be sticky..
I've been knitting socks for years, and use either bamboo or metal needles. I tried these out of curiosity, and was pleasantly surprised.
There's nothing that compares to the feel of bamboo needles, but I usually switch to metal when picking up gusset stitches or doing decreases. This avoids putting strain on the bamboo needles, which can be costly, and can bend over time. These plastic needles are sturdy enough for these tasks, and the stitches stay on the needles better than on metal ones. Knitting is fast, and the stitches glide along.
I think these needles are a good buy for new and experienced knitters.