I also had the old style G15 with blue LED-lit keyboard. At one point (about 1 year of use), one of the keys did not respond. I called up Logitech Tech Support right away, and they replaced the keyboard without any hassle.
I think the new style is better in that in the dark, it is still pretty difficult to see the blue backlit keys. I think the orange LED will work much better. If I have to buy a new keyboard right now, a G15 is definitely one of the top candidates.