So I said I would update on my status & here is my experience with asus service center:
All I can say is that I have really good experience with them. My zenbook was having some issue with the keyboard, I bring it to the service center in the morning (friendly staffs over there) explained the issue I was facing. Signed a form & thats about it. After 1 week plus the staff (its my friend actually) contacted me in facebook that the laptop is ready for collection.
Went there & they said they changed the lcd screen & motherboard (not sure why they need to change lcd, nothing was wrong with it but what the heck, I got new lcd it for free

). Thats about it I guess. RMA was quite fast IMO.
I believe if they have spare part on hand then it shouldn't take that long as you guys are complaining over here. Mine was a zenbook (premium laptop) so I guess they kept spare parts on hand. Also the lady next to me was keep complaining why they formatted her hdd & didn't install os in it. The lady told her its free dos version etc etc but she don't seem to understand
Overall it was a good experience for me, maybe they improved or perhaps just have spare part on hand but I didn't have any bad experience like what I see you guys are complaining. I was afraid regarding the RMA issue when I bought my asus laptop at first because I did come across this thread before but seems like my experience is different from what others have encountered.