There are many kinds that you should know about if you are planning on buying one. If you are looking for information on some that you have already bought then that is another situation. Keeping them and maintainign them really isn't that hard, maybe the same or as easy as chairs.
It makes a lot of sense to allow the swivelling to have space between each one. Some people like to have chairs at the same level so that they can blend in better and it just typically looks a lot better.
If you are wanting to make your new swivel bar stools match exactly you can always find somewhere the will let you choose what type of material to put on it, and you can even in some cases send your own in.
Bar stools in general have come a long way since the days of the old western saloons and now they are used in virtually every kind of setting.