I've done the half the last two years and Mike has run the half 3 or 4 times. He ran the marathon last year.
We are both running the half this year and I am hoping for a pr.
Unless they change the course, the half is pretty flat and fast. There is a hill (tunnel) going into and out of Churchill Downs which is steep and then a couple other small hills, but other than that pretty flat.
My only complaints--the corrals are a joke and the port of potties on the course are kind of hard to find (other than the start and finish).
Assuming the weather cooperates, there is a huge party on the great lawn afterwards and I think a beer coupon with your bib usually.
I'm probably not selling it very well, but it really is a fun half marathon.
The full has a bunch more hills and runs through some of the parks we train in. It can warm-up pretty quick in late April in Louisville which can make for a challenging end to the full. Mike has said it was definitely a one and done full for him.
Louisville definitely throws out the welcome mat around Derby, so it's a great time to visit.
ETA--and we seem to remember some stops in 2012 had cups and some had bottles...