Ever since I uninstalled Look Out and Juice Defender my phone is lightening fast. Both of these apps kill data connection. Look Out invades your privacy. Look Out constantly runs scanning your emails, files, everything. A geek at Verizon told me that Look Out is dangerous.
I use Adroid Assistant. I got the Nook 2 Android card, for my wife's Nook and it was an installed and recommended app on there. It allows you to clean-up/free resources, on demand and has several other features. I put the app on my Bionic, back in Sept. when I bought the phone.