I highly recommend checking out this thread on the Replica Prop Forum. The people here are amazingly helpful and the thread has been around since trailers for Tron: Legacy came out.
The people there have made costumes with all kinds of lighting methods. And if you do decide to use EL tape or wire there are lots f helpful tips on how to do the wiring and connections. Personally, I like LEDs, which are brighter and more power efficient that EL wire or tape...plus they do not need a loud inverter.
Just out of curiosity have you priced everything you'll need for the costume? Lighting can be very expensive, I know I had a bit of a nasty surprise when I bought everything I needed for my Quorra costume.