As everyone has said, yes, there is a big difference. But, from what you explained about the parts you plan to use and who will be shooting...it would not be worth the extra money. To make the most out of a KIDD receiver, you should use all KIDD parts which gets you the better manufacturing tolerances and the better accuracy. For the grandkids, who will never know the difference, the Ruger receiver will serve you well and save a bunch of money you can use to buy ammo. As NewsShooter stated, the cleaning hole is nice, but it is also very easy to add that to the Ruger receiver. Good luck with the build.