I've parked both at KLIA and LCCT for up to 1 week. So far it's been ok, security is decent and there are enough traffic going around that makes it "safer" but parking charges are expensive.

I personally would not park at Putrajaya Sentral, it's far too open and too quiet especially in the evenings/weekends. I agree with the suggestions above, have friends/family/taxi send you to the airport instead.