I have used the COOL Flex and I found it to be OUTSTANDING! I have used JB weld, and the original FerLTite, and I cannot recommend either. But, I will recommend the Cool Flex.
I use Gold Tips. When I called the FerLTite company, the gent I talked to suggested I use the Cool Flex when "experimenting" (trying to find the arrow length / insert weight you need). Installation, removal and reinstalling =of the insert is a snap! Once you've found the arrow length/insert weight you like, he then suggested I use the Pine Ride Archery Products "Instant Arrow Glue" on your insert. (I call it SuperGlue.) The Instant Arrow Glue WILL NOT allow the insert to come out (at least that is what I have found to be true).
Saying all that, I no longer go the route of using Sueprglue, and just stay with the Cool Flex. I find it easy to use, and convenient (I can replace the inserts with very little effort if needed (under heat of course). But, of course, the best part is my arrows stay together, even on a ToughMan course (OUCH!!!).
Regards!
David
P.S. I did hit a log on the Roanoke S.T.A.R. Toughman course, and the insert did come about 1/4", but I was able to put it back into the arrow. It hasn't come apart since... and I use that arrow daily! I have hit trees, I pull arrows out of old tough Mckenzie targets, the easy Reinhart targets and some not so friendly hard rock foam targets.
NOTE: I use to use the Saunders target/field points ... which are very smooth, tapered and go deep into a target. The bad part about the Saunder point is when they stick... the stick hard. It makes more work for the insert "hold".
Now, I use the 3 Rivers filed points (
http://www.3riversarchery.com/product.asp?i=CF511X )