I would assume that he is just going to get a led tube, which would be the same wiring up. If the CCFL kit required a seperate inverter, wiring would be more complex.
Leds are directional, which work well if done properly. Depends on the look he is going to go for. If you put a CCFL tube under the seat, the light would come out under all sides. If you didnt want that, a LED tube would be the way to go. It would be the same for under the glovebox. Using a CCFL tube, the light might come through areas of the dash that you didnt want it too. A led would get around this.
Colour could be a big thing though. I would imagine that CCFL's are a nice standard colour. ie if you buy 10 blue CCFL's from diff manufacturers, they will all look the same. If you were to buy 10 blue led tubes from diff manufacturers, they will all look a slightly different shade of blue.