I use Clean master (ks mobile).It seems to me the best,the only one i found that cleans also the microsd.Also it cleans himself (i appreciate it).It is also task killer but only if you want to use the option,otherwise it kills nothing.It "sees" more data (for example cache opera mobile,others don't clean it and i don't know why).Continuously updated,it has also other functions (backup apps for example).