THanks for all the replies above.
Well...I had some poor experience with MBP, in December last year I bought 17" uMBP, but there was a dead pixel on screen, got a replacement, then discovered the machine had the high-pitched (albeit not very noisy) electronic noise when adjusting screen brightness, returned it completely.
Then ordered online a this 15" uMBP with anti-glare screen hoping it will not have the same high-pitched noise (which drives me crazy in the evening, in quiet room)......Now I'm hesitating if I should open the box or just return it......could have been able to cancel it earlier but couldn't do it online (only after receiving it).