I've seen a friend's and also a hotel where the plaster ceiling colour is darker tone than the wall and I think it looks fabulous...

As suggested, you will need to test your own preference, one man's poison may be another man's meat..

You might hate or like it...BUT in my experience, you really need to test out 1 whole wall with the whole plaster ceiling painted

Just a small area will not give you the whole idea...

So you might need to spend EXTRA to test your own preference BUT than again, its better to have painted the whole house and then only decide to change and that will cost even more. This speaking from personal experience ;-) but its all up to you and your budget.

Hope that helps