wifi and bluetooth were off. don't know what an appkiller or juice defender is - I'm a droid newb...came over from blackberry. I did read a post about setting my email download frequency back. (currently at 15 minutes on yahoo email) I moved it to 30 minutes to see. Possibly will switch to my gmail account if I keep the device. The jury is still out.
I'm loving some of the features, but i run a business and outlook seems (on day 1 at least) to be much more elegant and business friendly than google mail/calendar.