I just bought a black, white, and stickerless 55mm Zhanchi, and they feel different to me. The black one is creaky (I feel the plastic "squeal" when I start a twist), while the white one is extremely smooth. The stickerless falls in between.
The differences are noticeable to me, but not heavily so. They're all still drastic upgrades from my two Rubik's brand cubes.
I refuse to believe that plastic of one specific cube color is "faster" than others, because if it truly were we'd all be using cubes of Color X, and we're not. I chalk up the differences in my cubes to be due to production variance from the factories.
As far as stickerless or stickered goes, I'm planning on using a stickerless as my main once I learn how to speedcube. I prefer having a cube that I can put in my pocket and go boozing and whoring and not have to worry about scratching up the stickers (because I'm totally going to be solving a cube while surrounded by booze and whores lol). I'll never be good enough to compete anyway, so I appreciate the convenience.
That being said, I'm using a black for the time being since most of the videos online use a black, and the uniformity helps when I'm learning. Mind you, stickers are cheap and you can always resticker your cube. It even looks kind of fun. I'm just lazy.
If you want some measure of portability and you don't expect to compete, I'd recommend stickerless.
If you're learning and you want as little divergence as possible between the videos and what you've got, or if you expect to compete, I'd recommend black.