I did a day with another org on Labor Day, and BOTH chicanes were open. Here's my (unprofessional) take:
The 2nd chicane has a good entry, and a bit higher speed throughout. It flows with the track fairly well.
The 1st chicane has an awkward entry, and really slows down the speed coming off the front straight. I don't like how it flows coming off the front. (Not to mention the bad entry onto the track coming off of pit road)
If both chicanes are open, man, you're gonna get a workout. It makes the entire track very technical. And for a 2.2ish mile track, it really leaves no place to "rest". Now, I'm a fatass, and those who are in better shape than I probably don't notice it as much, but it will kick your ass all day otherwise. If only the 2nd is open, I think it's a better layout than having both....
But I could be wrong.