223AI is a fantastic little cartridge with the only downside being that you have to fireform, but even that is fun.
You get a nice boost in velocity, never have to trim due to the shoulder angle, and I find it to be a little easier to load for/less finicky to powder variance and temperature changes. I'm running the 75 Amax in mine but am going to try the 80 ELD whenever I run out of those.
8208 is my choice as well but I have also had success with 2000MR.