Painted or stained cabinets in master bath?

It is actually a matter of preference. Some people like the symmetry and flow of having the same for cabinets in both spaces. Others like the complimentary look of using different colors/textures.

You can also base your decision on how far apart the master bath is from the kitchen. The closer the space, I'd use the complimentary painted look because I don't want to see anything from the bathroom in the kitchen! The further away I'd go for having the flow.

For me it would depend on the size of the bathroom. If it is a larger room stained cabinets won't feel like they are over taking the room, but if it is on the smaller side I would go with painted.