The difference of this method compared to task killers like "Automatic Task Killer" is that there is no separate application involved.
There is no widget or taskkiller process which needs to be run.
Instead you configure the Android kernel itself how to handle processes. While taskkillers need to be run regularly (automatically or by hand) to check memory and kill processes, the way I described this gets done complete automatically by the Android kernel, immediately when available memory goes under the configured limits.
There is also no need for ignore-lists or something like this, as the Android kernel knows which applications it can kill and which not. Furthermore you can configure much more fine-grained when to kill which processes and the kernel is using the internal "last recently used" list and kills the least needed processes first.
External task killer only can kill processes "blindly", they cannot see which processes are "empty" (not hosting an Activity) or which have been in the background for the longest time, and so on..
When people tell you that taskkillers are evil, they mean that taskkillers interfere with Androids process management in a way this was never intended. The way I described you still let Android handling processes itself, but you just tell it to be more restrictive.
So this is far less invasive into the Android system and (should ) have less side-effects..
But I'm still learning. I am a programmer who wants to understand things. And fortunately here we have the source to do so..