I saw this topic and wanted to weigh in on it.
I work on two shows where Bite Lights are used predominantly by the wardrobe staff. However, in a few select cases, an ear light or headlamp is used. Here is what I've noticed from this.
If you use a headlamp or or ear light, you MUST remember to turn it off! Many times, the crew doesn't remember right away, and there's a light flashing around backstage before they realize it's theirs. Obviously the advantage here, in a big way, goes to bite lights. If you need to turn your head to talk to someone, or look at someone else, you can instantly douse your bite light, but you can't always do that with your headlamp or earlight. A lot of times, staff is talking to the actor they are dressing and they look up to look them in the face and blind the actor, who needs to go on right away.
I also recommend if you go with a headlamp or earlight that you filter it in some way, either red or blue. This helps a lot when it gets inadvertently flashed around.
If how you look is important, go with the earlight, they are much less noticeable. I know two dressers who use headlamps, and everyone is always teasing them with, "So how was work in the mine today??"
Finally, even if you go with a headlamp or earlight, you should STILL have a bite light on a chain around your neck. You never know when it's going to just be easier to go back to the bite light in an emergency.
Mark