Is defense+ actually helpful to me?

Basically I really feel I need a HIPS but that has become that biggest decision for me.

I have seen Defense+ recommended and I understand its merits... If I wanted to stop my computer from doing anything without my permission.
My problem with it is it seems like, at least for me I would have trouble recognizing attacks.

For example what if I was running a program that was wrapped with some type of keylogger or something but the program normally does a lot of things when ran, for example a game or something. For a game you would also most likely see a global hook... is it the game or a keylogger disguised as the game.. etc

Any thoughts or suggestions on how these scenarios would look like in defense+ and if an somewhat above-average computer user would be able to recognize.

Thanks for easing.. or exciting my worries.