rice cooker and slow cooker are totally different. It depends on what is your purchase purpose.
I never bought a rice cooker. I just cook rice with a very common milk pot. Very easy. I just bought a slow cooker for chinese rice soup. I put all stuffs such as water, rice, green bean etc... in it in the morning. Then I have the soup after my work in the evening. Very convenient. BTW, slow cooker in Walmart is forsale now. It is around $13.