I use to love the led light on my bb and also bought the app to customize a color for each notification like when it is yellow i know it is a certain email account, green another, and etc. I really missed it when I first switched to apple but now I don't miss it at all... now I feel more relaxed and no longer a slave to my phone as I need to attend to it for every single blink it gives me (having the led flash at me just drives me nuts and makes me NEED to check the phone for whatever it is that I received). I also got to a point that when I see a color blink from something else I would think it's my phone and ended up looking at my phone every 15 minutes.
I mean it is useful but everything has it's cons and pros right? I think it really just comes down to personal preference... I wouldn't mind at all if the LED notification really comes true but I certainly do hope that apple gives us the option to turn it off...