I know. I own a Colt. It is OK but not worth what I paid for it. Colt was about the only company I knew of that was making them for civilian use when I bought it. It has the stupid, non standard lower they were using at the time. I basically paid a Daniels Defense price for a very plain Jane rifle. I have bought many since for less and every one of them works at least as well, even the $350 budget build I assembled. If Colt dropped their price to a reasonable level, I think they could compete. Whoever prices their stuff is nuts.
My sporter, which I got back in the mid 70's as a young teen, also has the non-standard lower/upper interface. Of all my AR builds/rifles, it is the only one I cant swap out the upper lower on with another AR because of this.