I am looking for opinions from people who have installed or used adjustable gas blocks on their rifles.  It sounds reasonable to me that it would be helpful. I am about to put my new freefloat tube on my Colt and since I will have it apart anyway, I wanted to know if I should make another investment before I start.  Also, is JP the only maker of adjustable gas blocks?  Thanks for the help!!

I have a JP on a varmint rifle. The gas block is of high quality. I did not see much of a difference with the adjustable gas block as far as taming the wicked recoil of the .223 in a 15 lbs rifle. I would not spend the money on it again if given the choice. Just not worth it.

For a competition rifle where you're running a low mass BCG - yes.  Evertything else - no.  

Well, that just saved me some $$$!
Thanks gentlemen and have a great weekend