Well, they're quite identical. Crucial would be the better choice as it's cheaper. I don't think overclockable and non-overclockable should be something to consider though as any RAM is overclockable. But as the crucial one says it is overclockable, it may give slightly higher frequencies when overclocked but I'm not sure if the difference in performance is noticable.
Besides, RAM overclocking is something I haven't seen much practised. Dual channel 3600mhz is fast enough for almost anyone.
There are other gskills for cheaper. Why not buy them? The one you linked is unreasonably expensive.
I've never seen anyone caring about anything other than CAS latency and clock speed. It probably doesn't make enough difference to care about. And spending 20$ more for something that won't be noticable isn't worth it imo.
I don't really have any specific favourite RAM or something like that. But usually as Gskill and Corsair are famous for their customer service and they are also widely available, i recommend Gskill/Corsair 3600mhz CL16 RAM. Something like this: https://www.newegg.com/g-skill-16gb-288-pin-ddr4-sdram/p/N82E16820232880?&quicklink=true