I took the
SCJP 1.6 exam today. There were two questions that dealt with the new topics. I am glad I went with 1.6 instead of 1.5. Sun's free retake promotion gave me confidence to do it.
By the way, I passed with an 87%, but that isn't why I'm posting this. If you are trying to decide which exam to take, I don't think it requires much more effort to pass the new exam. Just look at the javadoc and play with the code. It is really very simple (unlike the differences between 1.4 and 1.5). The passing score is a little higher, but you get more time to take the
test.