Sorry for the delay. The GT is faster than the normal voyager ... (so I have read in other reviews).
http://www.tweaktown.com/reviews/1097/2/page_2_testing/index.htmlI own both a Flash Voyager 8GB and Flash Voyager GT. The GT is much faster.
I have never had and issue to date using them. And vista works using the Voyager GT for 'Ready Boost' - although I am not sure the ready boost really does anything .... but that's another post.