From what I found when playing around with my ram, it generally takes +300 Mhz at +1 CL to break even in both benchmark and gaming performance, +400 Mhz +1 CL for any barely noticable gains.
200 Mhz per CL rating is completely unnoticeable at best, any bandwidth gain is offset by the fact that ram is never a bottleneck to begin with.
The best kit is the cheapest Samsung B die or Micron E die, and then manual overclock at CL14 as much as it will go up to 3800, or CL16 if you manage get a 4000+ capable kit, and use a latency calculator to find the best settings for your kit.