I'm a newbie but I've learned that most will tell you to try whatever sight, magnifier, ammo type that's good for you and your AR. I'll bet most of the guys here have many spare parts and probably I will too. I have three types of ammo to try next time out. I'm buying a Vortex Strikefire red dot because I can't afford an EOTech or Aimpoint yet.
I was told...if you like it, want it then get it. You can always sell things to others wanting them.
Just my two cents, hope it helps