They are not needed, android has a very efficent task managment process built into the operating system, any other application that claims to do the same will just work against the native processes and drain your battery
They tried telling my dad about it when he bought a case from there and the whole time I was telling him not to and her how she was flat out wrong. Fun times.
I was in the Verizon store yesterday and the salesman was going over the Droid 2 for a new user. The very first thing he started with was that "Verizon installs a task killer app for you..." bla bla bla.
I wanted to butt into the middle of his misinformation about task killers and tell the newbie how they aren't needed any more....but what's the use? This is the training and direction the salespeople are being given from the big red headquarters. The salespeople aren't paid to have a deep understanding of the technology...just to sell it.
I have butted in at VZW before, you could tell the sales lady was not happy, but her information was SO wrong, I couldn't help myself...the customer thanked me