We did ours with plaster, then painted it. Advantages are its cheaper, looks great, colour can be changed when you like, and looks clean. We had intended to do a timber ceiling, but got talked out of it by the builder, and are very happy with it now. Wood can be a little OTT too when there's a lot of it overhead, and painting or varnishing/dyeing is very difficult to get right. There will be enough wood on the floor if you choose that, otherwise its just too much.