I've have both in my case, 2 antec blue led fans, and 1 cooler master TLF-R82. I had to return the first TLF-R82 because one of the leds didn't work and the others would dim and brighten in no particular order.....
I vote for the Antecs hands down. Even though they only have 3 leds as opposed to cooler master's 4 leds, the leds are a lot brighter, and the fan looks a lot better. I also like Antecs fan design better too, it has the sunon type fins, the cooler master has the curved to the side type fins, which I dont think are as good (my opinion of course).
I still like the cooler master, and its pretty good for the money (the Antecs are more expensive), but IMO the Antec wins.
Oh, and another point is, the TLF-R82 has a 3pin connection and the Antecs have a 4 pin connection with a seperate wire for RPM monitoring. I've never checked the RPM's of the Antecs, but the Cooler master runs at about 2700 rpm according to MBM5.