what is the best optimization software?

i did a research on few optimization software such as onyx, macpilot, mackeeper and mac cleaner. i have a 2011 mba and i would like to know whats which one is better i don't mind paying for one. Any recommendations from user who have been using a macbook air for while. Btw does any of those softwares have internet optimization because i realize when i was downloading from the internet i am only downloading at 500kbs - 1.5mbs when i can download 5mbs on my desktop.