Yeah, the difference in timings is completely negligible (9-9-9-27 vs 9-9-9-24).
Just go with whatever one you think looks best. In this scenario, I would probably just go with the 1866MHz Memory. Either way you're getting some great stuff. It can't hurt to have faster memory, I only recommend against it solely because of the price premium (which is not an issue here).
Enjoy!