I just got a new upper to put togather my first AR. I intend to mount a scope first, I see that I can use mini risers with rings, or very high rings by themselves, or I can use a one piece base and rings. This is for a flat top DPMS bull barrel upper. So, which system do you prefer and why? I am leaning toward the one piece base and rings just because it is one piece and seems to be fewer parts to fool with and or go wrong.

Thanks..........

My first AR had the one piece from armalite.  I just bought my second gun and tried millet  rings.  They work fine, but I still prefer the one piece for what I believe to be more stability. (Fewer parts) I'm currently looking to replace the millet with a one piece.  
My opinion: Get the one piece.