I just bought a set of CCFL AE's and am about to put them on. I bought the ones with the plastic ribbed sleeve over the CCFL tube. When they are off, they look perfectly like OEM. The LED ones all have a yellow look (the LED color when off) or some do not use crystal plastic (use milky plastic to hide the individual LED's and to blur the image of each LED). I care about how my car looks when the lights are off as well, and the CCFL look way better than any of the LED when off.
In general, CCFL are the same tubes used in the BMW NAV display (backlight), all of your laptops, and most all LCD TV's. They really shouldn't burn out (typically 20, 000 Hrs on full time). Just as a reference: My car has 40,000 Mi and my car computer averages 18MPH (I live in a city). That means my car has been "ON" for 2222 Hours since new. That is no where near 20,000Hrs. The LED's life is highly dependent on being cool. I work in the lighting industry, and for all of our high brightness LED ribbons, we use a big aluminum heat sink (1" x 1/8" AL bar) to attempt to keep the LED cool so they will last anywhere near the 50,000 claimed hours. None of the LED angel eye kits use any heat sink! I would not count on the LED angel Eyes (especially the bright ones) to last anywhere near as long as a CCFL tube. The ballasts supplied with the CCFL are pretty cheap, and I could see them not lasting as long as they should.
So, from my perspective, I would rather change a ballast than have to keep cracking open my headlight assy to replace a ring with some crapped out LED's. If you really wanted to do this right, you would use a fiber optic ring (like BMW OEM) with a proper LED fiber optic driver (which have big old heat sinks to keep the LED's cool). That would be the "high end" route but it would cost a bundle..
Try pulling the LED band out of the plastic ring for a high brightness AE kit, hooking it up and leaving it to run for an hour. Then feel the LEDs. If the back side is hotter than 60 deg C, they wont last long. With LED it is the heat on the back side that matters, the light has no heat, it has to get rid of the heat out the part that is soldered to the ribbon/board. If it cant do that, it wont last long. There is no air flow under that plastic headlight cover. CCFL's love heat, their enemy is cool (which is why in really cold climates, they take longer to warm up to full brightness). At least temperature has no impact on life for the CCFL. It has a huge impact on the life of an LED.
Just my thoughts. If you are doing LED AE's you better go for the max warranty and hope the company is still around when they start failing.