I had not made a mystery quilt until this year. Now i have made 3. They are fun. I would have preferred a different "background" fabric on the 3rd had I known what the finished quilt looked like but it is okay the way it is. I have seen many mystery quilts at quilt shows that I did not like and thought I would never make one. Never say never!
I think you should give it a try. You can always donate the quilt if you hate it.