The reason why you'll like Fushigi Yugi is that they both have to search for 7 warriors who will help them save the world. The main character also falls in love with the guy she first meets who will protect her no matter what happens. Also, there is a guy who looks like a girl, but is actually a boy like Nachi.
They both have the very same feel when you read Dream Saga or Yume Yume You You.
They both have 2 worlds and have some magic and romance.
Yume Yume You You is cute and 'kya' worthy.
Whereas Dream Saga is more on the sirious side.
But if you like one, you're sure to like the other.