Hmm.

I'm tempted to say the blue one, since there's less contrast so it's harder to see any mistakes, but I also like the one on the far left. I feel like you got the shading just right on both of those two.

As far as the others...
The one second from the left has somethin' funky going on with the pattern you put on it. It's too flat, it doesn't follow the pot's contours.

Top-middle blends in with the background, my least favorite, personally.

Bottom-middle is two white. It's probably just the lighting but I can't seem to get over that detail.

I'm glad I stumbled into this thread whilst lurking around my first day here. Your other works are very inspiring, keep it up!