Yeah, well, as much as I'd love to upgrade to a ceramic series 4 next year, it's somewhat out of my price bracket I think, especially if I also want to upgrade to an iPhone Y (or whatever the heck they'll decide to call it...I would highly recommend people buying the ceramic edition to get Apple Care. Minimum service cost for out of warranty service for the ceramic version is $800.
Applecare costs the same for edition series watches as steel and alu? If yes, then it'd be well worth it I'd think. I will probably have to settle for alu again, but I'll do spaca grey this time, since my silver alu case hasn't scratched to any noticeable degree. I'd hate for the metal to show through the outer anodizing layer, which is why I went with silver the first time, but I seem to have worried over nothing.
Thus, based on personal experience I think space grey will be a safe, more stylish choice, because light color bands (to match lugs with the silver case) look grubby after some time of use. Yuk!