Nufletch fletching
 

Curious if anyone ever used nufletch fletching? It's a complete replacement screw in fletching. Claims to increase kinetic energy.

You mean to say
 

someones made obsolete my 4" vanes, my fletching machine and my glue.
I think I'll keep my obsolete stuff. I've been using that glue for over 20 years. And glue's pretty cheap.

Likewise. To the OP, just your asking makes me think of an old adage. There's a sucker born every day.

Well there is also another old adage that goes something like "Change is inevitable - Growth is optional."
At first I thought it was a gimmick too. But then I watched a show where they were using this fletching system on a hog hunt. The woman got a complete pass through on a decent sized hog using only a 36# DW and 27" DL. If you look at this system closely (and my first impression is that it is going to change your FOC %. But possibly not so) you will find that it is about 3" long. So that means your arrows can be cut shorter. Replacing vanes is as simple as unscrewing the nock, discarding the old vane and sliding a new one in and replacing the nock. Porbably a total of 15 seconds. You can refletch and arrow in about 30 seconds. And the vanes are Fusion vanes which are good quality vanes. The 'system' is supposed to stabilize your arrow faster and give you greater penetration. Is this true? Hard to say.
The hard thing to swallow is the price. $50 for 6 units. So if you smack a nock you just lost a little over $8 rather than about $.85 for a push in nock.