I've never had rice milk before, mostly because it is more calories than other similar choices. I like unsweetend soy milk but I love unsweetened almond milk. I also bought some unsweetened hemp milk but haven't tried it yet.
Darkblue - for soy milk, there are commercial soy milk makers on the market. There are a couple different ways to make 'milks'. You can make them at home as well. No chemicals involved.
http://www.soya.be/how-to-make-soy-milk.php