I have owned three AR's, A Rock River, a Stag, and a pre-selloff Bushmaster. I still own a Mini14. The Mini is going to be more reliable, but that is in the fringes like very cold or very muddy places. In the cold northern Alaska, guys who go with 223 go with the Ruger over the AR. In most other places they have the same reliability. Magazines are more expensive for the Mini, but at $30 each for factory 30 rounders that never killed it for me.
For some reason, I just flat out prefer the Mini 14 design. Part of the reason is that I have a Winchester Garand as well as an LRB M14 as well as an M1 Carbine. Transition between them is simple. Another reason is that I just prefer the cleaner, smoother lines of the Mini. But I don't feel the need to go Commando and attach things all over my rifle. I prefer mine to be pretty streamlined. I don't need scopes, lasers, lights, or extra grips everywhere, so rails and the like don't impress me. I have rifles that have scopes, of course, some hunting bolt guns and some snipers' rifles such as an NDM-86 and a PSL. For my use, at the farm, the Mini-14 fills every need I could ever want.
As much as I wanted to love the AR, and I dropped a couple of grand in the process of trying to love it, I never could. Other guys can enjoy them, fine by me, but for me and mine, the Mini-14 fits the bill. The only caveat I have is that the Mini I carry is a retired MS State Trooper GB model with flash hider and bayonet lug.
In the end, go with what rifle draws you. Which one is most interesting to you. That is what you will keep. For many, for most, that is an AR. For me, and many like me, it is a Mini.