Pretty broad question?
First, is the specific knife itself any good, a KaBar necker is a much better knife then a Grindworx neck knife, ergo, it would be a better neck knife. I'm currently wearing a Kershaw Blur in a kydex sheath around my neck, and I'll say it makes a pretty good neck knife.

I wouldn't want to try it with a Cold Steel large Espada though.
Next thing to consider is your wants and needs and such. Are they good for you, or any other particular person based on their needs?
I own a KaBar bk11 neck knife that I prefer to carry on my hip with a TDI clip, and just recently purchased an H&K Dispatch that I will for the time being prefer to carry on my neck via a lanyard because I'm not a huge fan of the belt option on said sheath.
So "are neck knives any good?"
Sometimes, yes and no, maybe, and it depends on what you're looking for and who you ask... But many of the knives themselves, deemed as "neck knives", are indeed pretty good knives... And oftentimes you don't " have" to carry them on your neck.