Agree with CNKS - although I'm a little more on the side of correctness. I'd prefer the mylar for that reason.
But I used vinyl on my most recent project as it was the only option. It looks nice, and even though it's not "correct" it looks natural enough like it's supposed to be that way.
They're easy enough to apply using windex on the location first which allows you to position the decal easily.
One problem I had was that the backing paper was very hard to pull off - it constantly wanted to take the decal with it on corners. In fact, it actually ripped the decal at one point.
So - if you go that route - move slowly and carefully (it's easy - you just have to go slowly and carefully)