Do you not like the current vanities' colors?

I think the wood one is lovely (though I have a bias towards wood), and I don't see a big change coming from painting the off white one to a different off white ... is it that you're changing the trim in there or something that you think will clash?

Keep in mind that painting cabinets isn't quite the same as painting walls ... it needs cabinet paint for durability/longevity ... if the painter is willing to add them on for cheap, make sure he's going to do it right, not just throw wall paying on the cabinets, especially if you're going to go with the same color as your trim. (Ask him what paint line he uses for the cabinets ... it should be something like Advance and not Regal, etc.)

I voted to paint yours as it looks dated. I agree to leave the wood and get a new top for it.

I wouldn’t paint either of the cabinets; especially the one in the kids room. The wood will hide finger prints sooo much more than paint would.