I've not experience with the PML driving courses. But I have attended the AB Advanced Driving Course.
For the RM1k that I paid at that time, I did think it was slightly overpriced (3 guys in a car, quite a bit of waiting around).
BUT, if you are NOT going to go all the way down to Singapore to attend the supposedly superior PML course (which I'm sure, will cost more), I urge you to attend the AB course.
Having some training is better than having no training at all.
EDIT;
BTW, the stuff taught at the AB course IS useful.