Its a personal choice weather to use the full on veil or not. Most of them are cultural. In the hadith (tradition) set forth by the Prophet Mohammad (sawa) it is said that the only things that do not need to be covered are the circle of the face and the hands. The things that would normally show. We are just expected that we shouldn't draw so much attention. I myself could not wear full face veil. Those women that do wear have GUTS because so many other people who don't understand it...they force their opinion of it either directly by saying so or indirectly by avoiding, staring, whispering,etc...at her.
As a revert...I would leave it up to the person. For those men that want to force coverage on the woman... they are wrong too.