I thought that Space Gray was the more popular one in all the polls
https://forums.macrumors.com/threads/iphone-x-which-color-storage-are-you-buying-merged.2066981/
iPhone X: which color/storage combo?
- X Silver 64GB
220 vote(s)
20.3% - X Silver 256GB
342 vote(s)
31.5% - X Space Gray 64GB
197 vote(s)
18.1% - X Space Gray 256GB
327 vote(s)
30.1%
I think it's almost 50-50. But in this thread every body seems to talk about Silver iPhone X