When I went a few months ago, there was no longer a discount for concierge guests. Both times I did, I was in a value studio-in 2008, the concierge guests got a $30 discount.
I'd say you have an excellent chance of seeing giraffes very close. Giraffes tend to be extremely curious. One of the animal keepers told me about Kidani, the giraffe born about 3 years ago. For a while he was on the savannah at AK, but they had to bring him back because he was trying to eat the windshield wipers on the trucks!