I spent the past week playing around with this set of Knook hooks and I love them. They're even smoother than the wooden hooks so the yarn glides along nicely. I already have the wooden ones and the "kids" set, so a comparison was easy to do.
I especially liked the large selection in this set since it has a couple of sizes that didn't previously come in any set, such as the K and one that's just labeled as a 7. The 7 is between the size G and H hooks and seems to be the one that works the best for me when using with cotton yarns. The smallest hook is also useful in making heavier socks...I'd use something other than fingering weight though, such as fine or sport weight yarn for that. The cords are plenty long enough for Knooking "in the round" to make socks or mittens without having to sew up a seam. The smaller hooks have a little more flexibility to them, which may help tighten up the gauge if you're having problems with that. The ease which the hook part goes through the yarn may also help tighten the gauge a little.
The cables also seem to be easier to thread through the hole in the hooks than the wooden ones are. Plus the fact that they're actually color coded so you know which cord to use with each hook is a nice little bonus.
The only thing missing from this kit is the clips to put on the end of the cords to keep stitches from falling off if you're making a large item. That's not a problem since I already have some from the other kits, and they're easy enough to find in any store.