I've actually found that that advance task killer works quite well when using it sparingly and my phone is still sleeping properly.
I got my Hero on November 30th, after the sms/dialer lock issue had been resolved. I noticed my awake time was at 100%, and went back to normal when I deleted ATK. I liked it while I had it, but when my battery went from lasting a whole day to 4-5 hrs while running task killer, I found I could do without it.