I was using InfiniteWP with great success and still think it’s great, but I ran across MainWP to manage all my sites. MainWP does everything InfiniteWP does and a whole lot more. With MainWP you can bulk install and activate plugins, and globally control almost every aspect of your sites.
I often use it to post articles and install new plugins across many sites. I update all plugins, themes and WordPress updates on a daily basis to ensure I avoid malware and hacking attacks caused by outdated software.