CK...been meanin to try some of those brass thingies! No! Wait! I forgot!! I can't stand them...yeah! that's it!
Honest. When I put on a nocking point I don't want it to move ever and I know exactly where it needs to be.
Last thing I want to happen is to shoot at a nice buck and find out my nocking point slipped at some point in time.
Scoob... It doesn't replace the glove or tab for me, but might make the string a little more comfortable for those who want to shoot bare finger or with gloves/tabs that don't offer quite enough protection.
It doesn't affect arrow flight that I can tell. If you use Fletch Tite or Duco you'll find it more prone to wear loose. It requires more maintenace with regular coats.
I didn't show it in the picture, but my preferred set up has the string double served above the arrow nock as well, but without the bump.
I find that it's a very positive way to nock the arrow. If you are anywhere near the middle of the string, the arrow can only fit in one place. (without forcing it)