While I agree with most people here that the crucifix is fine to wear, I think the distinction between Orthodox portrayals of the Crucifixion and the Catholic crucifix has to do with the second commandment forbidding graven (carved) images. In Orthodoxy, the image of Christ on the Cross is always flat, painted (written) in proper iconography. But the Catholic crucifix contains a three dimensional figure of Our Lord which is viewed by Orthodoxy as violating the proscription against graven images. I could be mistaken, but that's my understanding.
But like I said, I agree with most others here. God knows the heart, and I see nothing wrong with wearing a crucifix out of devotion to Christ and thanksgiving for His passion. But then again, I am not a Priest. Just offering my two cents.