I wouldn't suggest you Warid. Although, i haven't used it, but following is the comment by a fellow member digimanpk in the other thread, which says;
I am on Warid. This is whats going on in night.
Yesterday, I needed to call my sister around 1AM in the night, just to tell her to bring my stuff when visits our house in the morning. But I wasnt able to get through at all. I tried till 4AM in the morning but all i got was network busy, network busy. Imagine just this, My case wasnt an emergency, but If somebody would have needed to call in emergency where immediate access to other phones were not possible, what would have happened.
And this has never happened with me in Mobilink.