I prefer white always. And it looks better with any case.
Except a clear TPU one that yellows after only a couple months use. That keeps happening to me with my panda 2. I imagine that would be a lot less noticeable with a black phone.
I ordered the white Pixel 3 because the accent made it look awesome. Black looks pretty good too. I however did not really like the Not Pink.
Speck is claiming that their clear case will "Stay Clear".
https://forums.androidcentral.com/e...-3-xl-cases%2FGPX3L-PR-SC.html&token=b-zKur48
I have a clear Speck case on my white P2 that I've had since Dec. 24, and it is still perfectly clear. I even ran over it with my lawn tractor, and it still looks new! (chips in my screen saver, however)