fast or atomic efi ?

ive had enough of old school carbs, i'm gonna buy an efi kit this weekend but i can't decide between fast or msd. it sounds like either one are great here's some questions for ya.

-i'll be useing an external pump, which one is quieter ?
-i read that fast uses factory parts in their throttle body?
-which one is a cleaner install?
-has anyone had any issues with either system?