Love managewp. I really couldn't live without it.
Also awesome support and constantly being improved. I mostly use it to clone sites (create a dev version and a working version for backups). I use the automated backups and the SEO and the central admin to update plugins. I love not having to remember login info for all clients. I also use the cloning to move from one host to another painlessly and I've restored countless sites from the zipped backups in time of emergency.