I have Quilt Wizard. When I first got it, I spent hours just playing with possibilities! I, too, would use graph paper and colored pencils, and Quilt Wizard is so much easier!
A couple things to know...it is a limited program.
1. You can only use blocks in the library; you can't draw up a block and add it.
2. You are limited to the fabrics in the program. Now, there are tons of fabrics! I usually find a color I am thinking of using, then plug it in. I can get a pretty good idea of what my quilt will look like this way. It is easy to switch colors if it does not look right.
It has been a great purchase for me; it is lots of fun and worth the (lower) price!