i think its the radio update that's saving battery and not any task killer...task killers are useless on a linux based system just like antivirus...
So they say. However I still have my system memory being drained and then it returns when the tasks are killed. It also helps me not have to cycle through numerous returns through the k-9 mail app and my 5 email accounts as the system seems to remember every entry into the app and backs me through it as far as it can go... possibly eating up memory.