The North Face ECS @ Bear Mountain was very well run and organized. It's not over crowded and everyone is there to get dirty and have a good time.
There are yellow bus shuttles from parking to the start and sufficient port-a-potty's. The Half Marathon takes place on Sunday followed by the 10k and 5k. The half loops back in to meet up with the 5 and 10Kers for the last 2 miles. I didn't really mind this so much.
The Half marathon course is a brutal test. There are at least 5 climbs where you are doing little more than walking straight up or walking straight down. There is a particularly evil climb at mile 9.5 that will test your spirit. There aren't many opportunities to open your stride up, most of the trails are super technical footing that you have to pay strict attention to. Your quads and feet will take a beating.
There isn't much opportunity in NYC to run on terrain like this so if it's something you enjoy doing, I really recommend it.