IMHO... these are a must have for anybody with a M-16 or DIAS but still pretty expensive for a 22 given the cost of a Ruger 10/22 that will shoot all day without a problem...
I had a 22 conversion and I used it a whole lot with the M-16 but now that I don't have the M-16 to run the 22 conversion with I have no plans on getting another... For those that don't know, these conversion kits can be very picky about when they will shoot (too dirty, too clean, wrong ammo type = Jams, Stovepipes, and frustration).
Just a warning to those that may not know better... There are fixes including dedicated 22LR uppers and Kurt at Kurts Kustom used to make tons of them and they seemed to work much better without the 223 chamber adapter (using a barrel with chamber made for 22LR) but this is some serious $$$....
Good Luck.... I wish we could search back to the mid to late 90's and show the old posts!